Big problem when using WinRar with Visual FoxPro 8.0.

I'm working with a big database made in Visual FoxPro 8, and during programming I incontered a problem. The database I'm working with contains a number of arhives, arhives that have to be extracted, updated and arhived. The program used for this tasks is WinRar. The problem is that during the execution of the code, VFP 8 doesn't pause the execution to give WinRar time to perform the tasks given to him, and continues with the next execution line, and by doing so it messes up the database. I tried every thing, even using delay's but this is not a good solution, because on a slow computer they don't work. I'm opened for suggestions.
Thank you very much for your help.