Taser International ( TASR) slipped Friday after the stun-gun maker said it would not file its quarterly report for the period ended March 31 by the prescribed May 10 filing date "without unreasonable effort or expense."

In a filing with the Securities and Exchange Commission, the Scottsdale, Ariz.-based company said "its historical methodology for the calculation of indirect manufacturing expense applied to inventory was incorrect and also identified a clerical error in the calculation." Also, Taser said it found "a formulaic spreadsheet error" in the calculations for the fourth quarter of 2005. The changes will have no impact on revenues for the periods.

"As a result of these errors," the filing said, "adjustments were required to correct the cumulative impact both in the first quarter of 2006 and in the relevant prior periods." In the same filing, Taser said sales for the first quarter rose 36% from a year ago to $13.9 million and income would be a penny a share, up from break-even a year ago. Shares fell 82 cents, or 8.1%, to $9.32 in recent trading.

American Oriental Bioengineering surged after the plant-based pharmaceutical company said first-quarter revenue jumped nearly 98% to $19.1 million. The China-based company posted income of $4.9 million, or 8 cents a share, up from $2.2 million, or 5 cents a share, a year ago.

"We are very pleased to report a solid first quarter which resulted in strong revenue and earnings despite what is historically a weaker seasonal quarter," said Tony Liu, chairman and CEO in a statement. "The company experienced strength across all product lines which reflects the success of our efforts to continue to increase brand awareness and further penetrate underserved and rapidly growing markets throughout China." Shares gained 62 cents, or 12.1%, to $5.76 in recent trading.

Shares of Diana Shipping ( DSX - Get Report) slumped after the Athens, Greece-based shipping company missed Wall Street's first-quarter earnings expectations.

The company reported income of $11.7 million, or 26 cents a share, compared with $14.6 million, or 49 cents a share, a year ago. Voyage and time charter revenue totaled $24.2 million, compared with $23.9 million a year ago. First-quarter income and voyage and time charter revenue were reduced by $800,000, reflecting the non-cash amortization of the prepaid time charter revenue of the vessel Thetis. Analysts polled by Thomson First Call were looking for earnings of 30 cents a share.

The company declared a cash dividend of $0.345 a share, payable on or about June 8 to shareholders of record as of May 18. Shares fell 58 cents, or 4.7%, to $11.81 in recent trading.

Darling International ( DAR - Get Report) gained after the Irving, Tex.-based food processing by-products company said first-quarter sales totaled $76.4 million, up from $71.4 million a year ago.

The company said income dropped to $366,000, or 1 cent a share, down from $922,000 or 1 cent a share, a year ago. The company said the income drop resulted primarily from higher energy prices for natural gas and diesel fuel, increased operating expenses related to the start-up of its Fresno, Calif. modernization project, and higher legal expenses. Shares rose 10 cents, or 2.5%, to $4.18 in recent trading.