I have had trouble with Mondrian's schema caching mechanism - specifically if the filename/url matched, then it assumed that it already had the file. If I remember correctly, I used a servlet to return the schema, but appended the sessionid to the url - which allowed mondrian to recognize each user's as distinct. Not sure if this applies in your case, but may be worth a try.
Cheers.
2009-07-22 10:57:46 UTC in JPivot - a JSP based OLAP client
