thank you for your great feedback to my small problem (I'm learning a lot!)
just let me summarize, this should be the final product (sorry but I'm not confident at all with vbs):
'==== begin vbscript
x = replace(x, "c:/radmap/", "", 1, -1, 1)
I introduced a slight variation in order to save the output in a new file;
but I have another question now: is it possible to generalise the code so that it's processing all the files present in the same directory of the vbs file?