Not sure if there's a current source for supported client versions, but anything recently downloaded from steam is almost certainly not compatible. Post the first line from <your eq directory>\Logs\dbg.txt and perhaps we can figure out what version you have.
It looks like:
Code:
[Sun Jan 05 07:05:22 2014]00000:Starting EverQuest (Built Jun 8 2010 16:44:32)