[Brian]

File packages are a feature of Mac OS X - it's a folder that the OS knows to show to the user as if it were a flat file. This feature of the OS is what's causing the windows server to react badly. (It's not a permissions issue, in other words.)

I don't remember the exact details of what causes this - I couldn't tell you if it's the samba implementation in OS X or if it's a problem on the windows side.

My understanding is that OmniGraffle is making a regular cocoa "save this file" call; when that call happens to point at an XP and/or Samba share, the "this file is a package" bit gets mangled because XP has no idea what a file package is.

We added the "save this document as a flat file" preference in order to work around the problem; we weren't going to deny Mac OS X folks the feature because windows servers threw an error.