QTR-Quadtone RIP

I'm new to this program and when I loaded a .tif image to print I got 
the following error message in a red box next to the image preview " 
TIFF images not supported".  What am I doing wrong?

Hi Group,

I downloaded QTR a few days ago (updated to 2.6.0
today) and have been working at getting it going with
my Mac running Aperture and printing to an Epson R1800
with the MIS 3MK ink set.  

I'm printing on Epson Heavyweight Matte paper using
the Epson Enhanced Matte profile.  I tried printing on
Hahnemuhle Photo Rag using the photo rag profile but
it's not pretty...very muddy and dark.

My initial results with the Epson combination are very
encouraging, but the prints still need work; my blacks
are good (maybe a little too dense) but the whites are
gray.  The mid tones seem OK, maybe a little dark,
too.

Looking through the documentation on quadtonerip.com
there's a document called Quadtone RIP Users Guide,
which has a section on creating and editing curves
with Quadtone RIP.  Is that my next step?  It seems a
little drastic considering how close I seem to be with
the Epson paper.  But if so, then it leads me to my
second question; is there similar documentation
written for the Mac version?  

The Mac version doesn't appear to behave like the
Windows RIP; no stand-alone version that I can see,
and putting the RIP in calibration mode doesn't load
any ink separation file.  Opening the Ink Pattern Page
in Aperture yields wildly different results depending
on how you print it; in regular printing mode you get
proper-looking grey scale ramps that practically all
look the same.  Printing in Calibration mode produces
ramps with multiple patches of red, green brown and
several shades of purple...all very dense.

I notice that the instructions in the User Guide say
(in bold) "make sure the calibration slider is all the
way to the left (100)".  On my copy of the RIP "all
the way to the left" is 0 (zero), not 100.  100 is all
the way to the right.  Let me try another page with
the slider set differently.  

OK, with the slider set at 20 I get exactly the same
pattern but not so dense.  It's still full of reds and
greens, browns and purples but less dense.  For
example, the Light Light Black ramp starts white at
position 0 then ramps to black at position 40.  45 to
70 contain ramping shades of bright purple, and
positions 75 to 100 contain solid blacks.  My black
ramp has shades of purple and green and then is solid
black from position 60 to 100.

With the slider all the way to the left (zero) the
paper just flies through the printer because,
presumably, there's nothing to print.

Help!  I'm frustrated.  I'm getting unpredictable
results (in calibration mode) and for reference all I
have is a 3-year old document that I don't have a lot
of confidence in.  Is there an up to date document
that explains how to do this calibration with the Mac
version?  Is this even what I should be doing?

Any assistance will be warmly received and greatly
appreciated.

Thanks,

Ken Alexander