There is a chance that you can receive random "invalid floating point operation" errors in DBISAM when using certain printer drivers, specifically there are known to be some problems with some of the newer HP printer drivers (PCL 6). Downloading the latest HP printer drivers should solve the problem in most cases. However, if it does not solve the problem then reverting to a PCL 5 printer driver such as the HP 4 LaserJet driver should resolve the problem since these drivers do not exhibit this problem.

Note
There was also a problem with DBISAM prior to 1.19 that caused this error message and was not related to the printer drivers, rather it was a bug in DBISAM itself. Please make sure that you are running version 1.19 of DBISAM or higher to avoid confusion with the above issue.