subdomain forwarding

This is probably an easy thing to fix, but I need some help.

I am running wordpress mu on a shared hostrocket server. I had
hostrocket setup the virtual hosts/dns configuration necissary for me
to create subdomains w/in wordpress mu. Here's where my mod_rewrite
question comes in:

I have certain subdomains that I am running other processes on...for
example mailer.domain.org is my newsletter mailing program. it's
located in my /home/domain/mailer subdirectory. dev.domain.org is my
development area, and it's also located in /home/domain/dev
subdirectory. I'm trying to create a mod_rewrite rule that will
forward any http requests to mailer.domain.org etc to those specific
subfolders. Here's what I have - which I culled from a forum.

RewriteCond %{HTTP_HOST} !^(www\.)?knowmercy\.org$ [NC]
RewriteCond %{HTTP_HOST} ^(www\.)?([^\.]+)\.knowmercy\.org$ [NC]
RewriteCond %{DOCUMENT_ROOT}/%2%{REQUEST_URI}/ -d
RewriteRule [^/]$ %{REQUEST_URI}/ [R=301,L]

RewriteCond %{ENV:REDIRECT_STATUS} ^$
RewriteCond %{HTTP_HOST} !^(www\.)?knowmery\.org$ [NC]
RewriteCond %{HTTP_HOST} ^(www\.)?([^\.]+)\.knowmercy\.org$ [NC]
RewriteRule ^(.*)$ /%2/$1 [QSA,L]

It works for my mailing program, however it doesn't let me log into my
calendar program (events.knowmercy.org/login.php) that forwards back
to the knowmercy.org...I'm confused and in need of help.

Thanks

Chris Matera