Your regex doesn't come close to matching valid email addresses:

[A-Za-z0-9._%-]	matches one letter, digit, dot, underscore, percent or dash character
\@	an "at" sign
[A-Za-z0-9_%-.]	matches one letter, digit, underscore, percent, dash or dot character. Update: it gets worse: %-. is a range, so any one of '%&\'()*+,-.' would also match
.	any single character except a newline
[com]	matches the letter 'c', 'o' or 'm'

But unforunately both of them are matching .com.com

It matches much more than that:

/[A-Za-z0-9._%-]\@[A-Za-z0-9_%-.].[com]/ and say "'$_' matched"
  for 'x@zzc', 'a b c@c!c', '?@?@?e@a.m';
__END__
'x@zzc' matched
'a b c@c!c' matched
'?@?@?e@a.m' matched
[download]

As others have said, the only way to truly validate an email address is to send mail to it, and hope the owner replies.

Update: updated the second character class