If you've not played Skyrim in a long time and are trying SKSE, changes are that Steam updated your game to AE and you need to update SKSE. Sorry, I'm not referring to that. I mean, I always add some mods and then try to run the game when I'm building a pack, that's what ...
Check thatSKSEis running by looking at the logs inside %USERPROFILE%\Documents\My Games\Skyrim (I think that's right for Win 7 systems) ... it is evident at Skyrim startup ifSKSEis not running properly (or try opening anMCMmenu in game)....