Check your file paths or all input/output data.
Do you have any invalid characters such as spaces?
Check all the way back to the root drive letter
i.e. C:\Users\Bob\My Documents
this has a space between "My" and "Documents". This can sometimes make tools fall over. Replace all spaces with something else (I use underscores"_")
Or do you have hyphens in the file names? "-" Again, these will cause problems.
I hope this helps!
Dan