Xapplication and Linux

I have some problems of performances with my application developped with xapplication.

When it runs under windows XP, i have no problems.
When it runs under Linux (Redhat AS Release 3) my pages are very slow.

More precisely, it deals with a page that uses Rollback.
A page is modifying a document, and another is doing the rollback. The first call of the rollback-page is correct, and when a repeat yhe operation, the performances are going down.

Could you help me, please.
I’m really bad.