Upgrading to 2.5 is a disaster

I have upgreded WordPress 2.5 from the old version and afterward the following message appeared, see the code below. To try and fix the problem. I reinstalled the old WordPress and

1.) You can’t get to my site if you type https://motorparasi.com. You can get to the site using this address: https://www.motorparasi.com.

However, at the top of the web page, the following code appears:

“Warning: array_merge() [function.array-merge]: Argument #2 is not an array in /home/verotaro/public_html/motorparasi/wp-includes/widgets.php on line 53”

Plus, when I try to login my blog another message appears on the login page as follows:

“Warning: array_merge() [function.array-merge]: Argument #2 is not an array in /home/verotaro/public_html/motorparasi/wp-includes/widgets.php on line 53

Warning: Cannot modify header information – headers already sent by (output started at /home/verotaro/public_html/motorparasi/wp-includes/widgets.php:53) in /home/verotaro/public_html/motorparasi/wp-login.php on line 12

Warning: Cannot modify header information – headers already sent by (output started at /home/verotaro/public_html/motorparasi/wp-includes/widgets.php:53) in /home/verotaro/public_html/motorparasi/wp-login.php on line 24″

This is just a disaster for me: I can’t login my blog.

Can anyone help me with this problem?

Any help is greatly appreciated.

Thanks