Back to runrig's first reply, is the output from your original message the only output you're getting, or are other things showing up? I'd hope you're seeing the 'mkdir' and 'unzip' lines at least, in addition to the errors you provided.
Based on what's at LWP::Simple, the get() method can return undef if it fails. I'm not clear on what you mean by "does not work either" -- maybe it's not displaying anything? What if you try print "cb_ticker: [$cb_ticker]\n"; and see what shows up between the brackets?
You do appear to be displaying the value of $string1, which is what you're trying to retrieve - have you ensured that value is what you expect (I would guess you have, but can't hurt much to ask)?