Updated from 7:16 a.m. EDTApple Computer ( AAPL) has a credibility problem. Shares of the technology pioneer were climbing early Thursday as Wall Street celebrated an extraordinary third quarter and laughed off soft guidance, assuming Steve Jobs will find a way to overcome whatever obstacles exist. In a conference call Wednesday night, Apple warned that it expects software sales to slow in the current period and expressed concern about how an announced processor transition will affect sales of its Macintosh computer. The guidance was "prudent," said Tim Cook, executive vice president of Apple's worldwide sales and operations, on the call. Cook noted that the outlook still represents 50% revenue growth over the same period last year, adding that such an outcome would be "frankly stunning." Investors agreed with that part. In early trading Thursday, the company's shares rose $2.41, or 6.3%, to $40.75. Shareholders had much to like about Apple's report. In the quarter ended June 25, the company earned $320 million, or 37 cents a share, on sales of $3.52 billion. In the same period a year earlier, the company posted a profit of $61 million, or about 8 cents a share, on $2.01 billion in sales, meaning that the company's earnings more than quintupled on a whopping 75% jump in sales. Excluding certain stock-based compensation expenses, Apple would have earned $330 million, or 38 cents a share, in the quarter. Presumably on this basis, Wall Street had predicted that Apple would earn 31 cents a share on $3.34 billion in sales in the quarter, according to Thomson First Call. Back in April, Apple officials forecast the company would earn 28 cents a share in the quarter on $3.25 billion in sales. Looking forward, Apple projected it would earn 32 cents a share in the current quarter on $3.5 billion in sales.