Using CGI to output your hidden field might be a good idea as well. $q->hidden(-name => 'LOGDATA', -value => "$LogData");

You'll also find if @LogData contains any " or <> the ouput of your print statement will be messed up.
Use map or a loop to go through your array and substitute(encode) any dodgy characters .
Use single quotes to stop variables being interpreted i.e print '$line\r\n';
As Juerd says HTML entities should be useful you might also find the quotemeta function useful.