I am facing the same problem with ONLY one of my blogs (all on the same server) and starting from June 3.
It worked well before that day and still works well on all other blogs.
I tried all advised 'remedies' found on the link you provided, nothing helped and finally I asked Hostgator support so limit is increased to 64M,
but it didn't help too.
I am confused about memory limit because I have just a few sites, the biggest one has 350 posts, I am not using so many plugins...I wonder how people build a hundred' sites network all on shared hosting account...
My error message differs from that one above only by stating 'line 108'
instead of 'line 74'.
( DBM version 2.62 )
Anything else could cause the problem except memory ?