Solved K 3.0.3 + J! 2.5.9 + PHP 5.2.17: Library path __DIR__ cannot be found

I'm running Joomla 2.5.9
I installed Kunena latest release 3.0.3 on localhost and it runs perfectly. I then FTP the site on a live server and I got these errors: Fatal error: Uncaught exception 'RuntimeException' with message 'Library path __DIR__ cannot be found.'
Nothing is showing up but that error. It's also impossible to access the administrator login.
I believe it's a known error but I could not find a solution.

You get that only if your server doesn't meet the requirements of Kunena. You need at least PHP 5.3.1 to run it.

By default Kunena installer would prevent this from happening, but you used FTP instead.

Thanks a lot for your fast answer!. I just went to verify and you're absolutely right; the server version of PHP is 5.2.17.
This is bad. What is the solution? Are prior version of Kunena compatible with 5.2.17?
The thing also is that once you installed Kunena 3 then uninstall it to downgrade it to K2, there is an error message saying that you cannot downgrade.
Thnanks

Thanks

diarratech wrote: Thanks a lot for your fast answer!. I just went to verify and you're absolutely right; the server version of PHP is 5.2.17.
This is bad. What is the solution? Are prior version of Kunena compatible with [PHP] 5.2.17?

There are two solutions:

1) change your webhosting provider; this is the cheaper and better solution in the long run.

2) install an older version of Kunena that can work with PHP 5.2.17; see (a) Technical Requirements and (b) Download information (old versions of Kunena) ; older versions of Kunena are unsupported and you are fully responsible for resolving any problems you encounter.