It's OK I got it!!!
Realised the it should be oFiles...
ie.

with thisform
.filefinder.cFileExpression = oApp.ProdExe
.filefinder.cSearchPath = "c:\"
intFileCount = .filefinder.find(0)
if vartype(.filefinder.oFiles) == "O" then
if intFileCount > 0 then
messagebox("Found " + str(intFileCount) + "(s)")
strPath = .filefinder.ofiles.item(1).path
else
messagebox("No files found...")
endif
endif
endwith

Thanks for your help!