WASHINGTON -- Confusion over how to handle last year's rebate checks has led to over 3 million errors on tax returns, accounting for two-thirds of all the mistakes discovered by the Internal Revenue Service.

A report Tuesday from the General Accounting Office indicated that almost 7 percent of the 45.9 million returns processed through March 15 contained errors related to the checks.

That law also enabled people who didn't get a check or failed to get the full amount to claim a credit for their share on this year's tax returns, if they qualify. It is these claims that are causing problems.