I finnaly realize that I have problem with my new VPS server settings.
I tried to fresh install on my WAMP local server and on my online server and there is difference when I install user profile module on my local site there is captcha in registration form for new users, but on my online site there isn't. Also there is no any error message about this.
I have root rights on my VPS server so I can enable or disable any problematic settings that cause this problem. But I don't know what is the problem

My local site (WAMP) settings:
XOOPS Version XOOPS 2.5.4
PHP Version 5.3.8
mySQL Version 5.5.16-log
Server API apache2handler
OS WINNT
safe_mode Off
register_globals Off
magic_quotes_gpc Off
allow_url_fopen On
fsockopen On
post_max_size 8M
max_input_time 60
output_buffering 1
max_execution_time 30
memory_limit 128M
file_uploads On
upload_max_filesize 2M

My online VPS settings:
XOOPS Version XOOPS 2.5.4
PHP Version 5.2.17
mySQL Version 5.1.56-log
Server API cgi
OS Linux
safe_mode Off
register_globals Off
magic_quotes_gpc On
allow_url_fopen On
fsockopen On
post_max_size 8M
max_input_time 60
output_buffering
max_execution_time 30
memory_limit 32M
file_uploads On
upload_max_filesize 2M


I'm not sure if here is someone who know how to setup VPS so capctha start to work. Here are images from local and online site. On online site capctha part missing from registration form.

Local:



Online:



Please help, this is really big security problem for all my sites. Right now every day we have new registration of scam users on all sites.

...only thing I can't change is newer version of PHP or mySQL because of other clients that use some scripts that aren't supported in new PHP/mySQL version

I have no help with your requested issue, But I can help prevent a security issue.

This: allow_url_fopen On
Needs to be turned off in php.ini to prevent RFI attacks.

Thanks I set it to OFF

If someone else will ever need this info. I fixed this problem when I enabled TTF with EasyApache. Now captcha works.