Error 406 After Upgrade to 4.0.1

[DraCoola]

After manual upgrade from 4.0 to 4.0.1, I have an error like bellow while execute domain search script :

====================================
406 Not Acceptable

This request is not acceptable
________________________________________
Powered By LiteSpeed Web Server
LiteSpeed Technologies is not responsible for administration and contents of this web site!
=====================================



Switch to mod_suphp and the script just work fine.
Downgrade to 4.0 again still got the same 406 error.
Downgrade to 3.3.24 brought the same error either.
That script has just worked fine before this v4.0.1.





The error log from cpanel is :
----------------------------------------------
[xxx.161.63.xxx:10034-0#APVH_dxxxxx.com] File not found [/home/dxxxxx/public_html/406.shtml]
----------------------------------------------


My external App environment is :
----------------------------------------------
PHP_LSAPI_MAX_REQUESTS=500
PHP_LSAPI_CHILDREN=75
LSAPI_MAX_IDLE=5
LSAPI_PGRP_MAX_IDLE=5
LSAPI_MAX_PROCESS_TIME=300
-----------------------------------------------


Any idea how to fix this?