Wordpress wp-admin 503 The server is temporarily busy

[anything]

Hi.

I've moved a bunch of wordpress sites from one litespeed server (v4.0.17) to a newly setup and much more powerful server (v4.1.1) and now anytime someone successfully logs into a wordpress sites (/wp-admin) they receive an error "503 Service Unavailable The server is temporarily busy, try again later!"
The wordpress sites appear to work fine until someone successfully enters their username/pass in /wp-admin/.

The errors reported in the error log are something along the lines of the following (I've tried to remove anything too specific)

2011-05-29 03:33:35.785 [INFO] [66.114.50.55:35906-0#APVH_www.sitename.com] connection to [/tmp/lshttpd/APVH_www.sitename.com_Suphp.sock] on request #0, confirmed, 1, associated process: 21354, running: 0, error: Connection reset by peer!
2011-05-29 03:33:36.051 [INFO] [66.114.50.55:35906-0#APVH_www.sitename.com] connection to [/tmp/lshttpd/APVH_www.sitename.com_Suphp.sock] on request #0, confirmed, 1, associated process: 21358, running: 1, error: Connection reset by peer!
2011-05-29 03:33:36.052 [NOTICE] [66.114.50.55:35906-0#APVH_www.sitename.com] Max retries has been reached, 503!
2011-05-29 03:33:36.052 [NOTICE] [66.114.50.55:35906-0#APVH_www.sitename.com] oops! 503 Service Unavailable
2011-05-29 03:33:36.052 [NOTICE] [66.114.50.55:35906-0#APVH_www.sitename.com] Content len: 0, Request line: 'GET /wp-admin/ HTTP/1.1'
2011-05-29 03:33:36.052 [INFO] [66.114.50.55:35906-0#APVH_www.sitename.com] Cookie len: 441, wordpress_9216fec0724......bdace4fa=andrew%7C1306775590%.......aff92b5d4008c6; wordpress_test_cookie=WP+Cookie+check; wordpress_logged_in_9216fec0724fd8......ebdace4fa=andrew%7C130677559......26c60df843d3; __utmz=151998636.1306603282.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __utma=151998636.1131235342.1306603282.1306603282.1306603282.1; __utmc=151998636; __utmb=151998636.13.10.1306603282

/usr/local/lsws/logs/stderr.log reports no errors

As this site was working on the old server I suspected the newer php version was the cause of the problem.
But I have tried recompiling and using php to be 5.3.6, 5.2.17 and 5.2.14 (same as the old server) without any success.
5.2.17 was the worst, at random points random php scripts would terminate early.

I compared the results of phpinfo() between the old and new servers, and noticed the only difference was "Server API LiteSpeed V5.4" vs "Server API LiteSpeed V5.5". So I literally copied /usr/local/lsws/lsphp5/ /usr/local/lsws/fcgi-bin/ and the php config from the older working server to the new server. phpinfo() now reports 5.2.14 with API 5.4, but wp-admin is still not working and reports the same error.

APC is installed, but has been disabled for all my tests.

In my searches on the forums here I've seen several posts for the same problem but no solutions except for things like "i recompiled php and it fixed itself".

I'm lost as to where to go from here.
Any ideas?

Andy..