Three pieces of advice to avoid this in the future:
1
) install as many non-driver programs as possible to a Storage Card;
2
) check periodically during heavy use to make sure you have at least 1 MB of program memory available
(you can get by with less, but this is a good rule of thumb anyway
)
(Wolfgang Rolke's ResInfo gives you quick access to that information without having to go into the Control Panel
); or, better yet,
3
) get a 728 so that you have twice as much RAM to start with.