AGB 2.3.1 New bug?

Alright, after a lot of testing , there seems to be a new bug in the latest AGB:
This happens when u have included the guestbook in another php file(test.php) and activated picture uploaded.
When opening the guestbook within the other .php file, and trying to add an entry, there will be an error if u havent uploaded a picture.
But if uopen the guestbook directly (index.php) this error doesnt happen.

Is there any solution on this problem?

thx!

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