Redmine

Dear all,
I have the situation, that i once added a pdf in the document section to refer to and accidentally attached the same document later to an issue.
Will this work or not?
I am asking because I have "internal error" issues accessing this document via the document path.
As an attachment the document is still reachable.
I wouldn't know how to debug this, but maybe some of you will already understand by insight that it is doomed to fail maybe due to identical digest code in the MySQL table or something like that?
I tried a svn update and usual restart procedure but to no avail.

Here's my config:
0.8-stable branch via svn, revision 2337
ruby 1.8.6
Rails 2.1.2

Regards,
Michael