(Sorry for the following mess of a post. I wanted to get in important issue details but still keep the post to just a handful of paragraphs...)
Following an upgrade from DNN 4.0.3 to 4.3.5 we are now getting the "Arithmetic operation resulted in an overflow" error for one of our portals. The portal currently has 1.38GB of content. I've re-sync'd all portal directories via DNN File Manager just to be sure DNN was up-tp-date on its current portal content. We are using DNN 4.3.5 with Repository module version 3.1.10.15283. We routinely got the overflow error under DNN 4.0.3 when hitting 2GB of content on the same portal. We worked around it for many weeks by temporarily moving older content out of the portal folder when uploading new content, then moving the older content back into the folder.
Following the upgrade to DNN 4.3.5 I cannot upload any files with the Repository module (including small 2K text files) without getting the overflow error even with content at only 1.38 gigabytes. All files that were previously in the Repository (uploaded before the uprade to 4.3.5) have remained linked and available and can download and open without issue (docs, txt and PDFs).
I should note that our upgrade to 4.3.5 suffered the "extra slash" issue where all of our directory paths were appended with an extra slash in the database table "Folders" including the Repository directories. I.e., instead of "Repository/" we had "Repository//". I have reset the directory paths for two of our portals back to only a single slash, then re-sync'd the files and directories via DNN file manager interface. Both portals were then found to have an issue with Repository. i corrected the issue on one site that had not previously used Repository (see below). For my site already using Repository all files previously uploaded are still available. Our remaining portals that still have the "extra slash" are able to use Repository though those sites have other issues related to the extra slash. These sites eventually re-sync'd their contents and now have duplicate folder entries in the DB: one set of entries with a single trailing slahs and one set with two trailing slashes.
For the two affected portals: I can add files to the Repository folder using the File Manager so there is no core issue with uploading to that directory. I am able to upload with the core Documents module (ver 3.01.05) as well as the 3rd-party 'Document Exchange Lite" module from Bring2Mind (ver 3.00.07). I can add files using Text/HTML module and the new Media module. I have attempted to add an extra-slash for the "Repository" entry in the "Folders" table. I also tried adding an extra row in order to have one "Repository/" and one "Repository//" like our other portals have -- no luck.
Finally, for one portal that did NOT have the Repository module installed before the upgrade to 4.3.5 but DID have the "extra slashes" removed and files re-sync'd after the upgrade: I got a different error when attempting to upload with Repository. The error is "Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index." This gave me the idea to try re-pointing the Repoistory folder settings to a different folder. I changed all folders to point to the portal root and was then able to upload. Hurrah! Changing the folders back to Repository also worked. Unfortunately this same trick did NOT resolve the original "Arithmetic overflow" issue on my site already using the Repository module.
I'm continuing to investigate and hope this info may help someone else. In the meantime I'd appreciate hearing anyone's ideas on what we might try to recover operation of our Repository modules after the "extra slash" issue.