new install with 500 error

The .htaccess that is to be used with SEF Advance is in its zip file.
When uninstalled SEF Advance will remove its databases. If built-in SEF works SEF Advance should work as well if everything is fine with ionCube. I've seen some 500 errors due to PHP4 being used. Make sure you are running on PHP5.

Other than that, I can't help any more unless I can take a look on the site.

Hello,

I found the answer in a distant web forum: sh404 changes the structure of Joomla's core SEF tables. I wish I could look more into the details, but I think this means sh404sef can't be installed at the same time as advanced sef, and uninstalling sh404sef alone is not enough to restore joomla to default condition so advanced sef could be installed. I'd like to make an sql script which could prepare the sh404sef script fo advanced sef, but it would take me a long time, it's an area I'm still learning more about how the internals of sef work; and I only have one domain setup up outside localhost, so I'd also have to create a custom domain for the testing.