For one thing, try this:
$ xyz=hello
$ echo "xyz = $xyz"
xyz = hello
$
Shells look inside double quoted strings and replace variables. Your variable $ptscluster will be replaced before your local shell even locates the rsh command. This doesn't explain why you're not looping, but I'm not a csh expert. You should put scripts in an executable file, not in an argument to a command line. Once you use something like "rsh host ./remoteloop", all of the problems will vanish. Make sure you have a line like "#! /usr/bin/csh" in your remoteloop file. Note that you can create remoteloop locally, rcp it into place, chmod it, run it, and then remove it.