This is probably more of an Apache question than a Perl one. From my reading of the documentation, it looks like PATH_INFO should be available. The mod_include documentation says that all standard CGI variables should be available to SSI documents, the mod_cgi documentation says that all variables in the CGI specification will be set, and the CGI Environment Variables part of the spec includes PATH_INFO. So I'm not sure why you're seeing the problem you're seeing, but an Apache guru would probably know.