Take a look at the code for URI::Escape which you'll probably find at /usr/local/share/perl/5.10.1/URI/Escape.pm. In the current source for this module, escape_char() is coded right at the end:
...
sub escape_char {
return join '', @URI::Escape::escapes{$_[0] =~ /(\C)/g};
}
1;
If it's not there, you'll need to ask your server administrators to update their code. If it is there, please show the actual code you are running, i.e. with the calls to uri_escape() - the problem may lie with your implementation.