I'm going to guess that your problem arises from two issues. Please note that this is a complete guess because I don't see enough of your code to say anything more. I could very well be completely wrong.

1. $srch_host isn't being set or is mispelled. You probably need to add use strict; at the top of your script. That should catch a lot of spelling errors.
2. $LookFor is being concatenated to. That looks really weird, seeing as you're specifying the complete match with ^ and $. I would assign to $LookFor and go from there.

Of course, if you were to post a larger snippet, we would be able to see the issue(s) more clearly.

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We are the carpenters and bricklayers of the Information Age.

The idea is a little like C++ templates, except not quite so brain-meltingly complicated. -- TheDamian, Exegesis 6

Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.