HDCP is "High definition Digital Copy Protection". I have other names for it, but none that match up with the acronym. It was developed as an anti-piracy measure, and was used by some DVI devices. HDCP is a required function in any HDMI-equipped device, even though it's not a product of the HDMI licensing organization. An HDCP-equipped source component will not output a video signal until it negotiates an HDCP handshake with an HDCP-equipped display device. Putting any devices in between the source and display (such as an HDMI switch or a processor with DVI or HDMI switching like the 990) can add to the complexity, but even without that there can be cases where getting that handshake negotiated is problematic.

The other thing you didn't mention (as far as I could see) was the length of the cable to the projector and the other cables in the chain. HDMI borrowed its basic video spec from DVI, which was developed for PC's and includes a 15-meter maximum cable length. When you start to string together total signal paths approaching or exceeding 45 feet, you can run into problems as a result of this limit. A bad adapter could mimic a munch longer "distance" than the couple of inches of conductor inside it.