ok I ran phpinfo and got this under configure command:
'../configure' '--prefix=/usr' '--with-apxs2=/usr/bin/apxs2' '--with-config-file-path=/etc/php4/apache2' '--enable-memory-limit' '--disable-debug' '--with-regex=php' '--disable-rpath' '--disable-static' '--with-pic' '--with-layout=GNU' '--with-pear=/usr/share/php' '--enable-calendar' '--enable-sysvsem' '--enable-sysvshm' '--enable-sysvmsg' '--enable-track-vars' '--enable-trans-sid' '--enable-bcmath' '--with-bz2' '--enable-ctype' '--with-db4' '--with-iconv' '--enable-exif' '--enable-filepro' '--enable-ftp' '--with-gettext' '--enable-mbstring' '--with-pcre-regex=/usr' '--enable-shmop' '--enable-sockets' '--enable-wddx' '--disable-xml' '--with-expat-dir=/usr' '--with-xmlrpc' '--enable-yp' '--with-zlib' '--without-pgsql' '--with-kerberos=/usr' '--with-openssl=/usr' '--enable-dbx' '--with-mime-magic=/usr/share/misc/file/magic.mime' '--with-exec-dir=/usr/lib/php4/libexec' '--without-mm' '--without-mysql' '--without-sybase-ct'

should this really say "withouy-mysql"??

I am having the same exact problem. No errors in log. I can create db and tables in phpmyadmin. But I can not get past that page. The Db is empty and freshly created as xoops.
Linux Ubuntu
Apache 2
php 4
msql 4.0

how do you run phpinfo ?