I had the same problem with rewrite rules beginning with ^library. I changed the word to ^libary and everything worked fine.
When using ^library, the rewrite rule persisted even when I deleted the .htaccess file altogether, and GET variables were lost. Very bizarre.
Another site suggested that there was a possible conflict with an aliased folder on the host. However, in my httpd.conf there are no references to library at all.
It may just be an Apache bug. It would be nice to find a solution so I don’t have to rename the entire /library/ part of my site ??