I am having the same issue
Fatal error: Out of memory (allocated 66322432) (tried to allocate 68 bytes) in/home/XXXXXX/public_html/lib/weblib.phpon line 1202
Shared hosting at hostgator - Their reply is It appears your script is trying to utilize 66MBs of memory whereas the PHP memory_limit is 64MBs
I have 8 courses and about 200 people a day accessing the site. It is only with a recently added course I am getting this problem.
Before I go to VPS hosting I need to confirm that will in fact solve the issue.