dbmopen

Consider using a tied hash instead.

print "Content-type: text/html", "\n\n";

You can add the \n\n in the first literal string.

die;

You shouldn't die unless a real error occurs. Bad user input is not considered a program error, so it should not output to STDERR (everything that is output to STDERR is appended to the error log of the webserver). Consider using exit instead.

if ($fields{'updsynpass'}==""){

Don't use == for string comparison. Use the string equality test operator eq instead.

$fields{'updalumemail'}::$fields{'updemailpub'}:: $fields{'updalumsnail1'}::$fields{'updsnail1pub'}::$fields{'updalums +nail2'}::$fields{'updsnail2pub'}:: $fields{'updalumsnail3'}::$fields{'updsnail3pub'}::$fields{'updphone +'}::$fields{'updphonepub'}::$fields{'updalumyears'}::$fields{'updyearspub'}:: $fields{'updcomment'}::$fields{'updcommentpub'}::$fields{'updsynpass +'}::$fields{'updsynpass2'}"

Ouch. Consider using join instead. That would also fix your original %09-character problem. join is the exact opposite of split.

$synusers{ $fields{updalumname} } = join '::', 
    @fields{qw(updalumemail  updemailpub   updalumsnail1 updsnail1pub
               updalumsnail2 updsnail2pub  updalumsnail3 updsnail3pub
               updphone      updphonepub   updalumyears  updyearspub
               updcomment    updcommentpub updsynpass    updsynpass2)}
+;
[download]

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