No output to browser with no errors!?

[Sean P Quinlan <suppressed>]

OK, this is probably just a dumb programmer error on my part, but it is now almost 1am for me and I can't find anything in the docs.
I have a mod_perl (Apache & mod_perl 2 on SuSE 10.1) module destined to handle a requests for a set of possible URLs under a location.
	SetHandler modperl
	PerlResponseHandler CAS::Apache


The first one I'm working on is a simple login form; Here's the relevant chunk from CAS::Apache::handler:
	$r->content_type('text/html');
	
	my $html = $forms->$page();
	print $html;
	
	warn "HTML printed";
	return OK;
I go to the appropriate url, the page refreshes, but is completely blank. View source shows nothing in the page also. However the tail of my error logs does indeed show:
HTML printed at /usr/lib/perl5/site_perl/5.8.8/CAS/Apache.pm line 70.

As well as a few other bits. And I have added $HTML to the warn text and it all looks correct. I even tried just returning '<h1>Hello World!</h1>', but to no avail! Looking at the into and guides, it seems like I have the basic handler correct, the browser refreshes, and there are no errors in the log, but yet no body (header?!?) appears to have been returned to the browser.

Thanks!

--
Sean P Quinlan <suppressed>