RSS feed error

I have a problem with my feed link.

I’m using permalinks and I’m positive mod_rewrite is running on the serwer. The permalinks are working, all except the /feef/ link.

The rss and atom feeds when invoked via the ?feed=rss2 structure work, as well as invoked with /rss/ link, but the /feed/ links give me an error of

Parse error: syntax error, unexpected T_STRING in /myrootpath/gniazdoswiatow-net/wn/wp-includes/feed-rss2.php on line 9

Turning on/off the plugins helped none, I dug through the forums but found no valuable help in the similar threads so far.

Any ideas? Also, turning off permalinks is not an option. I’d rather edit the templates by hand and change all the links myself, but anyway, I’d rather receive some help, as I’m running out of ideas here.

The installation is brand new, freshly upgraded, but the problem existed in the previous version as well. There are no blank spaces / lines in the files associated with feed creation far as I was able to check it.

Any helpful ideas would be greatly appreciated.