Using incoming filename

Hi,

Just after the receive shape, I’m using an [i:b73c94e9a3]Expression[/i:b73c94e9a3] shape in my orchestration and here I need the incoming file name like this :
[code:1:b73c94e9a3]fileName = incomingMsg(FILE.ReceivedFileName);[/code:1:b73c94e9a3]
Then, I would like to use a [i:b73c94e9a3]Decide[/i:b73c94e9a3] shape to test if this file already exists in the BizTalk Server directory (\”c:\\data\\\” + [color=red:b73c94e9a3]filename[/color:b73c94e9a3]).
[code:1:b73c94e9a3]System.IO.File.Exists(@\"c:\\data\\\"+fileName)[/code:1:b73c94e9a3]
I have the following error :

[i:b73c94e9a3][b:b73c94e9a3]The given path’s format is not supported[/b:b73c94e9a3][/i:b73c94e9a3]

So the test always returns false even if the file already exists.
However, I can use the filename in the [i:b73c94e9a3]Message Assignement[/i:b73c94e9a3] shape because the output file named just like [color=red:b73c94e9a3]filename[/color:b73c94e9a3] :
[code:1:b73c94e9a3]outputMsg(FILE.ReceivedFileName) = fileName;[/code:1:b73c94e9a3]
[i:b73c94e9a3]Ex. Incoming file = coura38.fic – Output file = coura38.fic
If the file coura38.fic already exists in \”c:\\data\\\” the orchestration terminated.
[/i:b73c94e9a3]
It would be great if someone could tell me why this doesn’t work…