vb.net instruction causing setup problems

I have developed a setup.exe to install a program that I wrote. The program controls a data entry and extraction into a database. I built in a security feature such that if the database is accidently deleted a backup of it is copied to the working directory using the System.IO.File.Copy (from file, to file) instruction. Every now and then when the program on machines that it is distributed to it asks that the installation disk be inserted becuase it needs files from the disk that it says were not installed intially. Even after doing this once it pops up evey now and then and asks for the disk again. Does anyone have any suggestions? Is there a way to make sure everything in the program is installed? Any suggestions would be appreciated!