OSError [Errno 26] ?!?!

[Νίκος]

After making a slightly chnage inside my pelatologio.py script 
substituting '*****' instead of '-----' for no apparent reason i receive 
the following error:

[Tue Jul 02 06:33:06 2013] [error] [client 46.12.97.148] OSError: [Errno 
26] \\u0391\\u03c1\\u03c7\\u03b5\\u03af\\u03bf 
\\u03ba\\u03b5\\u03b9\\u03bc\\u03ad\\u03bd\\u03bf\\u03c5 \\u03c3\\u03b5 
\\u03c7\\u03c1

What is this OSError and these unicode characters besided it?
Here is the complete traceback.

[Tue Jul 02 06:33:06 2013] [error] [client 46.12.97.148] Original 
exception was:, referer: http://superhost.gr/
[Tue Jul 02 06:33:06 2013] [error] [client 46.12.97.148] Traceback (most 
recent call last):, referer: http://superhost.gr/
[Tue Jul 02 06:33:06 2013] [error] [client 46.12.97.148]   File 
"/home/nikos/public_html/cgi-bin/metrites.py", line 222, in <module>, 
referer: http://superhost.gr/
[Tue Jul 02 06:33:06 2013] [error] [client 46.12.97.148]     pypage = 
subprocess.check_output( cgi_path + page ), referer: http://superhost.gr/
[Tue Jul 02 06:33:06 2013] [error] [client 46.12.97.148]   File 
"/usr/local/lib/python3.3/subprocess.py", line 573, in check_output, 
referer: http://superhost.gr/
[Tue Jul 02 06:33:06 2013] [error] [client 46.12.97.148]     with 
Popen(*popenargs, stdout=PIPE, **kwargs) as process:, referer: 
http://superhost.gr/
[Tue Jul 02 06:33:06 2013] [error] [client 46.12.97.148]   File 
"/usr/local/lib/python3.3/subprocess.py", line 820, in __init__, 
referer: http://superhost.gr/
[Tue Jul 02 06:33:06 2013] [error] [client 46.12.97.148] 
restore_signals, start_new_session), referer: http://superhost.gr/
[Tue Jul 02 06:33:06 2013] [error] [client 46.12.97.148]   File 
"/usr/local/lib/python3.3/subprocess.py", line 1438, in _execute_child, 
referer: http://superhost.gr/
[Tue Jul 02 06:33:06 2013] [error] [client 46.12.97.148]     raise 
child_exception_type(errno_num, err_msg), referer: http://superhost.gr/
[Tue Jul 02 06:33:06 2013] [error] [client 46.12.97.148] OSError: [Errno 
26] \\u0391\\u03c1\\u03c7\\u03b5\\u03af\\u03bf 
\\u03ba\\u03b5\\u03b9\\u03bc\\u03ad\\u03bd\\u03bf\\u03c5 \\u03c3\\u03b5 
\\u03c7\\u03c1\\u03ae\\u03c3\\u03b7, referer: http://superhost.gr/

-- 
What is now proved was at first only imagined!