Yes, the permissions of FMS on the computer. It can only write to specific locations on the Hard drive. I suggest you rewrite the path definition to use the "Documents" folder. It should look something like this.
Set Variable $path_to_file =
& Get ( DocumentsPath )
& $file_name & ".fmpsl"
Where the variable $file_name has the file name to create. Then set the Email Attachment to be the new variable $path_to_file.
I had one adjustment I did not catch at first in your variable list and that I am still using v11 and it uses .fpsl extension. It kept trying to convert to v12 of which we are not switched to yet. Once I figured that out it works like I wanted. Thanks again!
I had some trouble with creating a snapshot on Server fm14 but this worked for me.
"file:" & Get(TemporaryPath) & "SnapShot_" & Round(Random * 999999999;0) & ".FMPSL"