I have a Mac mini C2D 2.0 connected to a Rotel RSP-1069, which feeds a 40' BJC BC-1 HDMI cable to my projector. However, the colors it outputs are pinkish, looking obviously screwed up. No bent pins or cables. I know because the strange thing is that both my Macbook and my Xbox 360 are fine.

Is there something about a DVI output that makes it less robust for longer cable runs, particularly on a Mac mini? I had read somewhere that you can play with the TDMS signal to make your output easier for HDMI-based systems, but I forgot where I read it.

I have tried several things:

Mac mini -> projector via 40' HDMI. 720p NO, 1080i NO
Mac mini -> projector via 30' HDMI. 720p OK, 1080i OK
Macbook with 30' and 40' HDMI cases: 720p OK, 1080i OK

So I assume that the Mac mini is susceptible to transmission issues over longer runs.

Then:

Mac mini -> Rotel -> projector via 3' DVI to HDMI + 30' HDMI. 720p Yes, 1080i NO. Also image is offset to the right by ~30 pixels and has a fushia line straight down the left side of screen.
Macbook -> Rotel -> projector via 3' DVI to HDMI + 30' HDMI. 720p Yes, 1080i NO. Also image is offset to the right by ~30 pixels and has a fushia line straight down the left side of screen.
Xbox -> Rotel -> projector via 3' HDMI + 30' HDMI. 720p Yes, 1080i Yes.

This leads me to believe that:
A. The Mac mini's output is not as robust as the Macbook's.
B. DVI-type output is not as robust as true HDMI output.