Based on the error message(s) - the resolution might be in the application code, within the data tables themselves, or within the configuration within the OS.
A data table issue MIGHT be resolved quickly or it may be a bigger problem.
* Messages like "Not a Database File" can sometimes be 'fixed' with 3rd party tools
* But it also might require going back to a backup copy.
An application code error should be relatively easy to resolve depending on the complexity of the code.
* Something like a "Divide by Zero" message will require patching the FP EXE's
* Corruption of application code files may require resorting to backups or de-compiliing.
Vista/Win7 OS's have their own unique requirements in order to run FP/VFP applications. If these considerations are handled properly, the application should run OK.
Like the previous individual asked - what version of Foxpro/Visual Foxpro are you using?
And what workstation OS is being used (some issues revolve around using the newer OS's)?
Lastly, did the application work before and now no longer is working?
* If so, then what was changed ANYWHERE in the system that the application is running on? That is quite often the likely source of the problem and needs to be investigated.