finsql.exe and high cpu usage

Over the past week our users have been unable to complete a posting into Navision. When they run the posting, Navision hangs and the cpu on the svr runs at 80\90%. If they leave it running, it can complete but can take 10-12 hours. As far as I am aware, nothing has changed (client or svr). The data they are trying to post involves around 1400 lines. Navision version is 5.0 (finsql.exe is ver 5.0.24199.0). It runs on SQL 2005 on Windows svr 2k3. Any ideas?Thanks.

Ignore the above. All working now. User error.