RMFRP says:
"This indicates that the target of the attack must parry for B rounds with a penalty of -A. The only allowable actions are movement and maneuvering (modified by at least -75). When A is not specified, it is assumed to be 0." RMSS also says "When B is not specified it is assumed to be one." But otherwise the wording is the same.
So, maneuvers are allowed, but with a substantial penalty. In fact, it's notable that the maneuver penalty is higher than the maneuver penalty while stunned.