When I log in as a user who is in a user group with permissions to add and edit their own items, I get an error page with the following explanation:

1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1 SQL=SELECT parent FROM aaq0x_k2_categories WHERE id =

The url is: poseyobserver.com/index.php?option=com_k2&Itemid=354&lang=en&layout=itemform&task=add&view=item

If I log in as a super user, I get: 403 You are not authorized to view this resource

Any ideas? I checked and double-checked the permissions in the K2 groups. What could I be missing?

Thanks,

Hello Michael,

Which version of Joomla! are you using?
Which other extensions are you using?

Joomla! 3.3.6 Stable [ Ember ] 01-October-2014 02:00 GMT
SH404SEF
JEvents
Ad Agency Pro
JFBConnect

Thanks

Try disabling them one by one to see which is causing this issue.
SH404SEF has been known to cause some issues (although not major) with K2's 2.6.9 version.