Upgraded to 2.5, now can’t login to admin and have warnings

Thanks Samboll. I followed the instructions, but got this error message when I ran upgrade.php:

Warning: require(/home/zachever/public_html/wp-includes/compat.php) [function.require]: failed to open stream: No such file or directory in /home/zachever/public_html/wp-settings.php on line 202

Fatal error: require() [function.require]: Failed opening required ‘/home/zachever/public_html/wp-includes/compat.php’ (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/zachever/public_html/wp-settings.php on line 202

Also, my site no longer appears online; I get the same error message as when I try to access wp-admin or run upgrade.php.

Kinda, Joni. My hosting company switched installers (from Fantisco to simple Scripts). The suggested gutting the whole site, installing 2.5 via Simple Scripts, and then adding the backup of the old site’s database that I made yesterday morning before I made any changes to the sites.

Through two hours of phone calls, we got the site to 2.5, but there’s still a problem. When I access the site or wp-admin page, I get this error:

Warning: array_keys() [function.array-keys]: The first argument should be an array in /home/zachever/public_html/wp-includes/widgets.php on line 678

Warning: Invalid argument supplied for foreach() in /home/zachever/public_html/wp-includes/widgets.php on line 678

Warning: Cannot modify header information – headers already sent by (output started at /home/zachever/public_html/wp-includes/widgets.php:678) in /home/zachever/public_html/wp-includes/pluggable.php on line 694

The Blue Host Level II rep said installing the plugins that I had previously should fix the problem. But without access to the backend, I have no idea how to do so.

He also said “You installed it without using the wp_ prefix for the database, which was used by your former database.” But I had to ask for clarification about what that means. Argh!

Thanks!