WoW doesn't load after patch to build 5238

A couple hours ago IS patched to build 5238. Now WoW won't load at all if i try to load it through IS like I used to. WoW works fine if I try to launch it regularly (without IS).

What happens is that it seems to try to load the first instance of WoW (I 2 box so it is set to load 2 instances of it) and it just hangs. If I start task manager it shows WoW as Not Responding. Restarting the computer, etc. doesn't help.

Nothing at all has changed on the computer except the patch to build 5238, so I assume the problem is caused by the patch. Running Win 7 64 bit if that matters at all.

Any help getting it to work again is appreciated.

[naPS]

Exact same problem for me - same specs on the OS as well.

However, it bombs out on random loads, sometimes it's the 3rd instance it won't load, sometimes the 4th, 5th, etc.

Also, when it fails, and I try to shut down the other WoW windows, they bomb out with an error asking me to send the info to blizzard.

[naPS]

Here's the error I get when hitting 'Quit' to get out of a WoW window :

This application has encountered a critical error:

Code:

ERROR #132 (0x85100084) Fatal Exception
Program:   C:\Program Files (x86)\World of Warcraft\WoW.exe
Exception:   0xC0000005 (ACCESS_VIOLATION) at 0023:14BD6D51

The instruction at "0x14BD6D51" referenced memory at "0x14BD6D51".
The memory could not be "written".

This morning first thing I was able to get WoW to load through IS, but upon exiting both instances of WoW I got the following error:

Code:

This application has encountered a critical error:

ERROR #132 (0x85100084) Fatal Exception
Program:   C:\Users\Public\Games\World of Warcraft\WoW.exe
Exception:   0xC0000005 (ACCESS_VIOLATION) at 0023:137F70D8

The instruction at "0x137F70D8" referenced memory at "0x137F70D8".
The memory could not be "written".

Full error dump at http://pastebin.com/YMSx9D0b

This was definitely not happening before the IS update yesterday...