Typo3 tx_realurl error

I was trying to install and make the tx_realurl plugin work but I always had this error:

Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, 'tx_realurl::encodeSpURL_urlPrepend' was given in /home/xxx/xxxxx/xxxxx/typo3/t3lib/class.t3lib_div.php on line 4432

After searching the internet and reading a few forums, I found the following solution:

I changed the access modifier of encodeSpURL_urlPrepend() in class.tx_realurl.php line 328 from protected to public.

This seems to be a bug of the 1.8.0 version of tx_realurl.