I am currently migrating some courses from Moodle 1.9.18+ to Moodle 2.5.1 and some are failing with a strange error message: "Error writing to database / Error reading from database". I have attached a screenshot. The error occurs after pressing "Continue" on the "2. Destination" step (where you select the Course Category).
I'm aware that User Data doesn't restore when making this jump between these versions but we are okay with that. I exported the courses from 1.9.18+ with User Data = None.
I've set the Debug Messages (debug) setting to both NORMAL and ALL but no debug information is appearing on screen. I have also confirmed that the "Display debug messages" (debugdisplay) setting is set to Yes.
The courses are around the 55Mb mark but I've allowed up to 128Mb upload size and the actual upload step works without a problem. I can also uploaded the zip to the "User private backup area" first but restoring from there didn't help either.
I have also cleared out the moodledata/temp/backup folder and this didn't help.
Can anyone point me on how I can identify the course of the error message.