joomla函数需要致命错误

I have a problem which suddenly appeared on my site... It seems like a problem with php version on my hosting but don't know how to fix it and could use any help...

My site runs on J 1.5.16 (I know it's not up to date...) and yesterday was running just fine.

the error is:

Warning: require(/templates/xxx/gk_suckerfish.php) [function.require]: failed to open  stream: No such file or directory
in /home/xxx/public_html/templates/my_template/index.php on line 22

Fatal error: require() [function.require]: Failed opening required '/templates/my_template/gk_suckerfish.php' (include_path='.:/usr/lib/php:/usr/local/lib/php')
in /home/xxx/public_html/templates/my_template/index.php on line 22

Thanks!

I have found a solution!

It seems that somehow the legacy plugin was disabled, I have enabled the plugin system-legacy and the site works fine again!

Now I really have to work on upgrading the website to at least j 2.5

P.S. The real problem was with j 1.5.17. which has serious issues with auto disabling the system-legacy plugin. I have updated the site to 1.5.26. and do not have this problem anymore!

Thank you all, Best regards!