Take a look into system/user_avatar/index.php.
Search for $upload->max_filesize after this line place the following code:

$upload->max_image_size(yourwidth,yourheight);

In the nect release there will be 2 new settings for the Picwidth and -height under Admin -> User Avtar -> Settings.

In forums under users posts installed buttons as ICQ, AIM, YM and other, but under this buttons used links like as http://wwp.icq.com/scripts/search.dll?opnparams=AHYBYlA8C2oDYVswVGBWNQw3AmUFMwRj - of course, this links is incorrect...

Bug found, fixed and checked into SVN.

How can I block an ip-adress from entering to the phorum or portal?

First. Please for a new question a new Topic.
Second you can block an IP via .htaccess.
When you enter:
order deny,allow
deny from IP
allow from all

in your .htacces you can block a IP. If you will block more then one IP separate the IPs with , in the deny from