I'm using VS2008 with the following Hotfixes
(KB946308 ) KB946308
(KB946344) KB946344
(KB946581) KB946581
(KB947171) KB947171
(KB947173) KB947173
(KB947180) KB947180
(KB947540) KB947540
(KB947789) KB947789
(KB948127) KB948127
and llblgenpro 2.5 final March 28th 2008
I tried uninstalling v2.6, reinstalling v2.5, creating a new Web Application, regenerating my DAL and still had the problem.
The solution: I deleted all of the llblgen generated code. Generated it from scratch, rather than regenerate into the existing folder.