EXCEL 2007: File name with blanks
 

I'm using EXCEL 2007 via a Citrix-Session. When I try to open (with double
click) the existing Excel-file 'c:\temp\mein test.xlsx' with ending .xlsx
and a blank in the file name (or path) the following happens:

An information window occurs with the message " 'c:\temp\mein.xlsx' cannot
be found. Check your spelling, or try a different path."
After clicking OK a new attention window occurs with the message:
"'test.xlxx' could not be found. Check the spelling of the file name, and
verify that the file location is correct. If you are trying to open the file
from your list of most recently used file, make sure that the file has not
been renamed, moved, or deleted."

I click OK and - oh wunder - the file opens.

But what is going wrong? When I rename the file to MEINTEST (without blanks)
the file opens immediately ...

Thank you all for any help!
Ulrike