zwepp

Some extra info as requested:

– WordPress up to date? YES
– NextGEN up to date? YES
– What version of NextGEN Gallery did you upgrade from? (i.e. I had 1.9.13, then upgraded to 2.0.61) Sorry, I didn’t look at the older version, it was really old.

(please confirm the following, with your server host tech) :
– MySQL up to date (at least 5.0)? YES
– PHP up to date (at least 5.2.4)? YES
– The mod_rewrite Apache module activated? YES
– PHP Safe Mode OFF? YES

Now I checked with the Twenty Twelve theme and everything works fine there, so there is something wrong with my current theme (customized Mygrid2 theme). Is there any idea where I can start looking to resolve this? Thanks again.