I don't really know what is happening at your end, but this seems

$_ = "but you might try looking at /home/monks/thanksforhelping1234567
+890.ext for help";
$_ =~ /(\/home\/monks\/thanksforhelping\d+\.ext)/;
print $1;
[download]

to output:

/home/monks/thanksforhelping1234567890.ext
[download]

So check for typos... that could be your problem