I'm able to select a valid event from pull-down list, but event does not save. Problem seems to be random - just some documents have this problem.
Some examples:
http://www.geni.com/documents/view?doc_id=6000000016858298013
http://www.geni.com/documents/view?doc_id=6000000016823396010
I see a similar bug report that was fixed:
http://help.geni.com/entries/427344-upload-document-to-event-will-not-attach-to-the-event-bug
Using Windows 7 w/IE 8
To reproduce:
Select existing document
Unknown Location (Edit) -- P.S. Not sure why their isn't a generic "Edit" Document link
Choose an existing event
Save