RScript.exe and map directory issue

Hi,
I'm trying to run on Windows 7 a scriptfile with Rscript.exe from within
Excel 2010 with the following code:
Call Shell(rPath & "\Rscript.exe C:\Work\Latest\_Test.R", vbHide)

The good news is: the above code works perfectly, but ...

If I add white spaces to my map directory, like:
Call Shell(rPath & "\Rscript.exe C:\Work\Latest 1\_Test.R", vbHide)

In the above case or the RScript.exe doesn't run the file anymore.
Could someone explain to me how this comes and how I can deal with it?

Kind regards,
Bert