(SOLVED, <s>to the extent it actually needs to be, further minor issues are still here if you care</s>)

I'm at Day 3 of one of those Learn The Bare Bones Of X Language In Y Days tutorials. If you'll hit End, you'll see the exercises I'm supposed to be doing. I'm having a bit of trouble with 1, though; this is my response to it (after much slimming-down): 
#!/usr/bin/perl -w
use strict;

$count = .0;

until ($count == .9)
{
    $count = $count + .1;

    print ($count, "\n");
}

print ("End!\n");

[download]
Before I added -w and use strict;, the script would go into an infinite loop of this sort: 
685.700000000087
685.800000000087
685.900000000087
686.000000000087
686.100000000087
I'm sure it's something to do with the fact that I'm using floating point values. When I replace them with whole numbers, it counts one to ten then prints End! just wonderfully. I've tried zero-padding the values (as in 0.9 instead of .9) as well; this makes no difference. When I added -w and use strict;, I get this: 
-bash-2.05b$ perl count
Global symbol "$count" requires explicit package name at count line 4.
{same for $count at lines 6, 8, 8, and 10}
Execution of count aborted due to compilation errors.
Am I supposed to be declaring $count as a floating point variable somehow?

I searched and found a post or two that said something about trying to compare floating point values being a Bad Idea. Am I doing something wrong, or will this just never work?

In reply to Floating point number counting script stuck in a loop by Vonunov

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