Setup Apache2::AuthenNTLM for External Authentication and now RT is slow

I have setup single sign on using Apache2::AuthenNTLM and ever since
then the system is slow at times and sometimes seems to hang. I am
getting a lot of lines in the error log like the following and maybe
that has something to do with it. Is there a better alternative for
External Authentication

[Mon Jun 09 13:05:54 2008] [error] Bad/Missing NTLM/Basic Authorization
Header for /

[Mon Jun 09 13:06:15 2008] [error] Bad/Missing NTLM/Basic Authorization
Header for /

[Mon Jun 09 13:06:22 2008] [error] Bad/Missing NTLM/Basic Authorization
Header for /Admin/

[Mon Jun 09 13:06:32 2008] [error] Bad/Missing NTLM/Basic Authorization
Header for /index.html

[Mon Jun 09 13:06:55 2008] [error] Bad/Missing NTLM/Basic Authorization
Header for /Tools/index.html

[Mon Jun 09 13:06:57 2008] [error] Bad/Missing NTLM/Basic Authorization
Header for /Search/Results.html

[Mon Jun 09 13:07:00 2008] [error] Bad/Missing NTLM/Basic Authorization
Header for /NoAuth/css/3.5-default/main.css

[Mon Jun 09 13:07:01 2008] [error] Bad/Missing NTLM/Basic Authorization
Header for /NoAuth/css/print.css

[Mon Jun 09 13:07:01 2008] [error] Bad/Missing NTLM/Basic Authorization
Header for /NoAuth/js/util.js

[Mon Jun 09 13:08:22 2008] [error] Bad/Missing NTLM/Basic Authorization
Header for /Search/Chart

-Willy