When I try to install Drupal 7 on a shared hosting environment where I have a properly working D6 install I get a 500 Internal Server Error. I do not get this error in my dev environment on a local Ubuntu machine.
When I check the logs, I see htaccess: regex could not be compiled.
I am installing the D7 in the same location as the D6.
If I comment out the FilesMatch section or replace it with the corresponding D6 FilesMatch in the htaccess file, I do not get this error. But I cannot imagine that this will not cause some other problem.
The D7 FilesMatch is:
# Protect files and directories from prying eyes.
<FilesMatch "\.(engine|inc|info|install|make|module|profile|test|po|sh|.*sql|theme|tpl(\.php)?|xtmpl)(|~|\.sw[op]|\.bak|\.orig|\.save)?$|^(\..*|Entries.*|Repository|Root|Tag|Template)$|^#.*#$|\.php(~|\.sw[op]|\.bak|\.orig\.save)$">
Order allow,deny
</FilesMatch>
The D6 FilesMatch is:
<FilesMatch "\.(engine|inc|info|install|make|module|profile|test|po|sh|.*sql|theme|tpl(\.php)?|xtmpl|svn-base)$|^(code-style\.pl|Entries.*|Repository|Root|Tag|Template|all-wcprops|entries|format)$">
Order allow,deny
</FilesMatch>
If I just put the htaccess file in the root -- without the rest of the drupal install or anything else -- I get the same results. An error with the D7 htaccess and no error with the D6.