[Joel]

This is due to a change in Leopard, we've found out that the 'as "foo"' parameter doesn't work, however a UTI or CFBundle TypeName will. Quoth the OmniGraffle Team Lead:

After some investigation I think the problem is that Apple changed the interpretation of the "as foo" parameter in 10.5.

The new behavior requires either a UTI or a CFBundleTypeName (it uses the new NSWorkspace type:conformsToType: method to search for a matching type in the list returned by -writableTypesForSaveOperation:; the method expects UTIs but is documented to take "other type names, including those declared in CFBundleTypeName Info.plist entries", which is a good thing because the strings that -writableTypesForSaveOperation: returns are not UTIs. It's not clear what other ways of specifying types might be accepted also.)

Right now it works if you specify a CFBundleTypeName string. From the release notes it looks like we can make it accept UTIs as well. The CFBundleTypeName strings in Graffle at the moment are: "OmniGraffle Format", "Apple PDF pasteboard type", "NeXT TIFF v4.0 pasteboard type", "PNG", "JPEG Format", "EPS Format", "HTML Image Map", "HTML Directory", "OOOutlineDocumentType", "Scalable Vector Graphics XML File Type", "PICT", "Photoshop", "BMP", and "VisioXMLDrawingType".

The other workaround is to leave off the "as foo" entirely; AppKit will guess a format from the file extension.

We're working on a better fix for the future, in the meantime this does work as a workaround.