To handle run time error

I assume that you are using VBscript. 

I am not familiar with VBscript. Normally I would suggest using a try/catch statement, but http://stackoverflow.com/questions/4999364/try-catch-end-try-in-vbscript says that VB script does not have this feature.

Alternatively maybe you could look into event handlers: http://support.smartbear.com/viewarticle/56222/