I installed the Download Mod 5.0.7
When I create a category from control panel and try to access he download section, I get the following message probably because the category is empty.
Fatal error: Cannot use string offset as an array in .../dl_mod/classes/class_dlmod.php on line 455
I've now re-uploaded the new 5.0.8 with your changes.
Please use the new class_dlmod.php (the update from 5.0.7 to 5.0.8 and changing the MOD release number on database)...
EDIT
Now (17:30) I updated the package again.
I found a wrong initialization for the array.
Fixing this and using your changes the download index might now works errorfree on empty categories.
Still replace the class_dlmod.php...