VFP7 - Windows 2000 Small busyness Server

Email_Dir = "T:\SAM_MAIN\SCIL\"
.
.
.
if not DIRECTORY(Email_Dir)
MKDIR(Email_Dir)
endif

The MKDIR-line causes very scarcely the error:
Error: 1961
A subdirectory or file t:\sam_main\scil already exists.

The subdirectory is actually there but why did DIRECTORY() not see it?
Is there a way to make it more secure?

Thanks in advance
Peter