1. As per OM troubleshooting guide, if the power light is blinking red at 0.5 sec intervals it is may be the speaker impedence (what are yours?) or a stray or faulty speaker wire or connection. Particularly suspect are the tightly packed connectors on the back of the AVR. Is this an open box unit? I would consider resetting the microprocessor if we can't get this resolved.
3. Check that the correct antenna is connected to the correct posts.
Ha-ha, jd is beating me to the answers again!
You're probably right, those look like junk cables. Inexpensive but reliable cables are available from forum sponsors Monoprice (and also Blujeans), see the top of your page for links. For today, you may have to hit radio shack or BB. I would buy as short a cable as will easily do the job.