EAA had a more complete explanation:

FAA TEMPORARILY RETRACTS SPORT PILOT PROPOSAL
Action Allows FAA to Answer OMB Questions


March 25, 2004 - FAA Administrator Marion Blakey ordered an
administrative move on Wednesday, March 24, that keeps the sport
pilot/light-sport aircraft rule on track for final approval this spring. She
withdrew the proposal from the Office of Management and Budget (OMB) to
answer several final questions about the rulemaking package.
That maneuver saves the rule from facing a potential significant delay
in its approval. By bringing the proposal back to FAA, Blakey can address
OMB's questions in the most expeditious manner and return it quickly for
final approval.

March 24 marked the end of OMB's 90-day review period. Had FAA not
retracted the rule, OMB could have rejected it, severely delaying issuance
of a final rule.

While expressing disappointment in the 11th-hour development, EAA
President Tom Poberezny commended FAA's decision and acknowledged it as the
best way for the agency to address OMB's questions and secure a final rule
as quickly as possible.

"This is a temporary timing setback," he said. "EAA continues to
champion and support the sport pilot/light-sport aircraft rule, as evidenced
by the considerable resources we've dedicated to developing programs and
services for our members, including the introduction this week of EAA Sport
Pilot & Light-Sport Aircraft magazine." Poberezny also noted an upcoming
announcement regarding a major sport pilot and instructor training program.

FAA officials confirmed to EAA that answering OMB's questions about
the proposed rule is a top priority.