I assume you're trying to use Gzip compression for faster downloads of assets and text content. It's a great technique for speeding up your site.
Safari, Chrome, and IE6 all have problems with Gzipped downloads. Also, Apache will do the gzip compression for you, there is no need to manually gzip files. Try this snippet:
# This uses mod_deflate, which is pretty standard on Apache 2. Loading
# mod_deflate looks like this:
#
# LoadModule deflate_module modules/mod_deflate.so
#
AddOutputFilterByType DEFLATE text/html text/plain text/xml application/xml application/xhtml+xml text/javascript text/css application/x-javascript
BrowserMatch ^Mozilla/4 gzip-only-text/html
BrowserMatch ^Mozilla/4\.0[678] no-gzip
BrowserMatch \\bMSIE !no-gzip !gzip-only-text/html
That should safely gzip all text before it's sent out from Apache, and only for browsers that support it. You can link to JavaScript and other assets normally, just myscript.js, with no gz extension or compression on disk.