The process to rebuild a database involves copying the RMD file to another location and then selecting to Rebuild from the Reference Manager software. This will re-index the database and create a new RMX file. Please see our knowledge base article with those instructions:
http://help.thomson.com/default.asp?portalid=TSC&article=84799
You can create a backup copy of the RMD and RMX files before you follow these steps. If the problem persists, please contact Technical Support: