/webmail giving a 500 Error

[optize]

cPanel has an alias /webmail which goes to:

ScriptAliasMatch ^/?webmail/?$ /usr/local/cpanel/cgi-sys/wredirect.cgi

That script seems to work:

root@cpanel [/etc/httpd]# /usr/local/cpanel/cgi-sys/wredirect.cgi
Status: 301
Location: https://cpanel.server.com:2096

However, when clients go to it (all domains) they get a 500 internal server error.

I've turned on debugging and this is what it spit out:

----


2013-03-02 07:36:46.731 [NOTICE] [my.ip:54851-0#APVH_domain.com] Content len: 0, Request line: 'GET /webmail HTTP/1.1'
2013-03-02 07:36:46.731 [INFO] [my.ip:54851-0#APVH_domain.com] Cookie len: 101, wordpress_logged_in_cef<cookie values>
2013-03-02 07:36:46.731 [DEBUG] [my.ip:54851-0#APVH_domain.com] Check Symbolic link for [/usr/local/cpanel/cgi-sys/wredirect.cgi] is successful, access to target [/usr/local/cpanel/cgi-sys/wredirect.cgi] is granted
2013-03-02 07:36:46.731 [DEBUG] [my.ip:54851-0#APVH_domain.com] processContextPath() return 0
2013-03-02 07:36:46.731 [DEBUG] [my.ip:54851-0#APVH_domain.com] ScanPost: 0
2013-03-02 07:36:46.731 [DEBUG] [my.ip:54851-0#APVH_domain.com] run cgi processor.
2013-03-02 07:36:46.731 [DEBUG] [uds://usr/local/lsws/admin/cgid/cgid.sock.141] request [my.ip:54851-0#APVH_domain.com:cgi] is assigned with connection [0x141515c0]!
2013-03-02 07:36:46.731 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] MOD: 2, UID: 1031, GID: 1024
2013-03-02 07:36:46.731 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] [ExtConn] reconnect()
2013-03-02 07:36:46.732 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] [ExtConn] connecting to [uds://usr/local/lsws/admin/cgid/cgid.sock.141]...
2013-03-02 07:36:46.732 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] ExtConn::onWrite()
2013-03-02 07:36:46.732 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] CgidConn::onWrite()
2013-03-02 07:36:46.732 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] request header is done
2013-03-02 07:36:46.732 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] ExtConn::continueRead()
2013-03-02 07:36:46.732 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] Request body done!
2013-03-02 07:36:46.732 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] ExtConn::suspendWrite()
2013-03-02 07:36:46.732 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] ExtConn::suspendWrite()
2013-03-02 07:36:46.732 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] processNewReq() return 0.
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] ExtConn::onRead(), state: 2
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] CgidConn::onRead()
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] [EXT] EndResponse( endCode=0, protocolStatus=0 )
2013-03-02 07:36:46.740 [NOTICE] [my.ip:54851-0#APVH_domain.com:cgi] Premature end of response header.
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] HttpIOLink::continueWrite()...
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] write resumed!
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] ExtConn::onEventDone(), fd: 240, state: 2, event: 17, revents: 16.
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] HttpIOLink::handleEvents() events=4!
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] HttpIOLink::suspendWrite()...
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] HttpConnection::sendHttpError(),code=500 Internal Server Error
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] redirect to: URI=[/500.shtml], QueryString=[]
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] Find context with URI: [/], location: [/home/username/public_html/]
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] Find .htaccess context with URI: [/], location: [/home/username/public_html/]
2013-03-02 07:36:46.740 [INFO] [my.ip:54851-0#APVH_domain.com:cgi] File not found [/home/username/public_html/500.shtml]
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] Error Page, processContextPath() return 25
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] HttpConnection::flush()!
2013-03-02 07:36:46.740 [DEBUG] [my.ip:54851-0#APVH_domain.com:cgi] Written to client: 642

--

Any ideas?