[Koha] error when I try to translate koha

[gustavo]

Helo!

We have instaled Koha few days ago on a Debian Etch server (perl 5.8.8), 
so it's running perfectly. Now I am trying to translate koha to spanish 
following the information I've found in 
/koha/koha-3.00.00/misc/translator/translator_doc.txt

koha:~/koha/koha-3.00.00/misc/translator# ls
install-code.pl  po               stats.pl          text-extract.pl   
TmplTokenizer.pm  TmplTokenType.pm     translator_doc.txt  
VerboseWarnings.pm
install.pl       rebuild_lang.sh  text-extract2.pl  tmpl_process3.pl  
TmplToken.pm      translator_doc.html  update.pl           xgettext.pl


When I run the script ....

koha:~/koha/koha-3.00.00/misc/translator# ./tmpl_process3.pl install 
--input=/usr/share/koha/intranet/htdocs/intranet-tmpl/prog/en 
-o=/usr/share/koha/intranet/htdocs/intranet-tmpl/prog/es 
-s=po/es-ES-i-staff-t-prog-v-3000000.po -r -q


... I get some warnings:


Charset in/out: UTF-8 at ./tmpl_process3.pl line 257.
% s: Unknown or unsupported format specification


I think that the first one ("Charset in/out: UTF-8 at ./tmpl_process3.pl 
line 257") is not really a problem, just information about locale. But 
the second line ( % s: Unknown or unsupported format specification) is 
really a warning about an error, but I don't know exactly  what does it 
mean and wich is the solution


Do you know whether  it is a bug  or  I'm doing something wrong?

Gustavo