As mentioned, 2 and 3 are going to be case sensitive because they are regex. 1 should probably work, but why not just try without the fourth parameter? 0 isn't listed as a possible parameter, though I haven't tried it to see if it would do anything.
You should try manually doing it from the command line...
//echo -a $fline(@text,%text-to-find,1-100,1)
//echo -a $fline(@text,%text-to-find,1-100)
Make sure you set %text-to-find to something first and then see if you get any output from a valid search.