Updated from June 29

Research In Motion's ( RIMM) stock stumbled in after-hours trading Wednesday after the company's second-quarter forecast fell shy of the Street's earnings estimates, and the company offered little news on a long-running patent dispute.

In early Thursday trading, shares of the BlackBerry maker were down $2.85, or 3.8%, to $73.06.

The plunge came despite the fact that the company posted first-quarter earnings that were a penny above analysts' forecast, reported strong growth in revenue and subscribers to its BlackBerry service and offered better-than-expected third-quarter numbers.

In its first quarter ended May 28, RIM earned $132.5 million, or 67 cents a share, helped in part by a tax credit. That result was up from the same period a year earlier, when the company earned $55 million, or 28 cents a share.

Revenue surged 68% year over year to $453.95 million.

Excluding the $26.9 million tax credit, related to a ruling in Canada, and after-tax legal expenses of $4.5 million, RIM would have earned $110.10 million, or 56 cents a share. The legal expenses relate to the recent resumption of its patent dispute with holding company NTP. An announced settlement in that case fell apart earlier this month.

On average, analysts polled by Thomson First Call were expecting the company to earn 55 cents a share on $452.15 million in sales for the quarter, ostensibly on this pro forma basis. The company previously predicted that it would earn 51 cents to 56 cents a share on sales ranging from $430 million to $455 million.

RIM had not disclosed how the failure of its recent settlement talks would affect its earnings for the just-completed and coming quarters.

Though the company came in above analyst estimates for the just-completed quarter, it warned analysts to bring down their forecasts for the second quarter. The company now expects to earn 57 cents to 63 cents a share in the current quarter on revenue ranging from $465 million to $490 million.

RIM's earnings guidance matched the range the company gave back in April, while the revenue outlook was actually up by $5 million on both the low and high ends of the range. But the midpoints of the outlook -- earnings of 60 cents a share on about $477.5 million in sales -- were below analysts' estimates. Wall Street had forecast that RIM would earn 61 cents a share on $482.1 million in sales in the current quarter.

Though the company now believes second-quarter revenue will be better than previously expected, it expects gross margins to decline "slightly" in the second quarter from the first, said company CFO Dennis Kavelman. Gross margins, which represent the difference between what customers pay a company for products and services and the direct costs to the company of providing those goods and services, fell from 56.8% in the fourth quarter of last year to 55.1% in the just-completed quarter.

RIM introduced an update for its enterprise software in the fourth quarter. Strong sales of that software, which RIM sells at a higher profit margin than its BlackBerry pagers, boosted the company's overall revenue in the fourth quarter, Kavelman said. Gross margins declined in the current quarter because of moderating sales of the enterprise software, a trend that will likely continue in the coming two quarters, he said.

Perhaps adding to investor concerns about the company's guidance, RIM said little about its ongoing dispute with patent-holding company NTP beyond what it has already announced. The companies announced in March that they had agreed to settle their dispute, but RIM warned investors earlier this month that settlement talks with NTP have fallen apart and that the row is heading back to the courts.

Beyond the already disclosed legal maneuvering, "there is nothing new to report" in terms of the lawsuit, company co-CEO Jim Balsillie said on a conference call.

RIM plans to maintain the accounting treatment for the settlement that it had outlined previously, said Kavelman on the call. The company expensed the bulk of the proposed $450 million settlement amount in its fourth quarter last year.

Since an unfavorable appeals court ruling in December, the NTP dispute has weighed heavily on RIM's stock. The case could potentially result in RIM being barred from selling its BlackBerry products in the U.S., by far the company's biggest market.

But even though the company didn't do much to assure investors on the NTP front, it did offer some positive news.

Subscription growth, for instance, continued apace in the just-completed quarter. The company added 592,000 subscribers to its BlackBerry service -- a 24% jump, sequentially -- and crossed the 3 million subscriber point for the first time. The company expects continued strong growth in the second quarter, forecasting that it will add 620,000 to 650,000 new subscribers in the quarter, which would represent a 20% to 21% quarterly increase.

But that too may have spooked investors. Even at the top of that range, sequentially subscriber growth would be the slowest it's been in eight quarters, potentially indicating a slowing of the company's overall growth rate.

Kavelman, however, chalked up the projections to expected seasonality of its business, noting that corporate demand tends to soften in the summer. And with consumer purchases becoming more important to RIM, that seasonal fluctuation in the company's business could increase.

RIM expects to post a higher subscriber growth rate in the third quarter, Kavelman said.

Thanks in part to that expected surge, the company offered third-quarter guidance that was above the Street's outlook. RIM expects to post a profit of 62 cents to 68 cents a share in the third quarter on sales ranging from $525 million to $550 million.

At the midpoints of that range, the company is expecting about 65 cents a share in earnings on sales of roughly $537.5 million in the third quarter. Analysts have predicted a profit of 64 cents a share on $522.4 million in sales for the period.

Additionally, company officials attempted to address investors' concerns about the competitive threat from Microsoft ( MSFT). The software giant plans to update its Exchange e-mail software later this year to incorporate features similar to RIM's BlackBerry service. Some analysts have worried that Microsoft will steal some of RIM's market share because Microsoft is offering the wireless e-mail features for free as part of the Exchange upgrade, while RIM charges customers for its BlackBerry server software.

Microsoft's service may be nominally free, but that doesn't mean that running the service won't come at a cost, said Balsillie. Companies will have to take the time and expense to upgrade to the latest version of Exchange, he noted. The handheld pagers that can tap into the Exchange service are typically pricey, he said. And the service will be data-intensive, meaning that corporations that use it will have to sign "expensive" service agreements with wireless carriers, he said.

"If someone is representing that it costs less, that's not a true statement," Balsillie said. "Far from costing less, it's quite a bit more expensive."

RIM has a leg up on Microsoft, because the architecture behind its system offers better security than Exchange's system, he said. Meanwhile, RIM's system will work with pagers from a far greater number of manufacturers running a broader array of operating systems, he said.

Corporate information officers "want a generic platform" like RIM's, Balsillie said. "They've told us that unanimously."