See the PHP code for that link: http://forum.php.pl/index.php?showtopic=29670
Entered here with no issues found: http://phpcodechecker.com/
See the PHPLint report attached as yxy file - has invalid escape sequence in string
ERROR: unknown constant s4uext - problem: http://forum.php.pl/lofiversion/index.php/t29670.html
Should be e.g in the footer.php like: include(“adstat.html”);
The address htxp://stat.4u.pl/ is blocked by an extension in my browser - HTTP-Switchboard 
What kind of tracking was blocked: htxp://www.skar.pl/ htxp wXw.skar.pl * / analytics 312 380 2015-03-20 00:46:52 (-adstat.4u.pl|stat.4u.pl) htXp://adstat.4u.pl/s4u.gif -stat4u
htXp://adstat.4u.pl/s.js?masterkomp htXp adstat.4u.pl /s.js analytics masterkomp 312 380 2015-03-20 00:46:57 (-adstat.4u.pl|stat.4u.pl) htxp://adstat.4u.pl/s.js?masterkomp -stat4u
- blacklisted website infesting with Avast detecting JS:Decode-BML [Trj]. We are being protected.
polonus