you could try using Win EQ2 to load all your boxes through 1 client. it allows you to keep seperate INI files for each window and each character which would allow you to keep the gfx turned down on all but your main etc.
http://www.lavishsoft.com/
ISBoxer would also do the same thing but its not free, 10 bucks for a 3 month subscription and it would also depend on the server rules, im sure there are some servers out there that would frown upon use of isboxer since it allows some features that are similar to "that which will not be named" :P
as for the specific issue i honestly have no idea, i had something similar happen while running from the same client, maybe try removing your character/ui INIs from your second client and starting fresh - could be an issue there?
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