Just a quick problem I came across in SharePoint today when trying to edit a file:
The folder structure being used was fairly complex, unfortunately this meant that a filename only had to be a few characters long to exceed this rule. Unfortunately there does not appear to be an easy way to fix this issue other than reorganizing the folder structure.
One workaround is to simply press the “Open with Explorer” button and edit the file that way. Thankfully the url limitation does not effect files reached through this method.
This link has a bit more info for anyone who may be interested.