The Senate bill contains fees that could be considered tax provisions, which under congressional rules are supposed to originate in the House, according to House and Senate aides who requested anonymity because they were not authorized to speak about the situation.
House Republicans could call a vote to send the bill back to the Senate for another vote. That could hurt the bill's chances as Congress rushes to wrap up for the year.
A Senate aide said the problem was caused by a misunderstanding between Senate and House floor staff.
A spokeswoman for Sen. Tom Harkin, the Senate sponsor of the bill, said the senator is confident the two chambers can resolve the issue.