[Zope] File url in a network

[F. Troester]

Hello,

I need some help. I don'n know how to specify a file url in a network.
For uploading and creating an object (within the Product External File) I
need

<dtml-call "uploadCreate(target_filepath=target,upload_file=fileurl)" >

with the file_url as upload_file.

I get the error

[Errno 2] No such file or directory:
\\192.168.1.172\C:\FH-Unterlagen\Vorlesungen\MT\KFZ-MT\Folien\Temp\Titelblat
t.pdf 
when I use this function with the 
fileurl='\\192.168.1.172\C:\FH-Unterlagen\Vorlesungen\MT\KFZ-MT\Folien\Temp\
Titelblatt.pdf'.

How can I specify the file in the network?

Thank you for an advice
Fritz Troester