[particlewave]

Do you have an ammeter? DVMM?

I plan to get a set of these this summer and will get it working and post a diy. Until then, there aren't enough details on the circuit to even begin to guess whats going on. I found a better picture of the wiring, but it doesn't show whats going on inside.
Are all of the leds just wired to the male bulb connector without their own resistors? Are the individual leds wired together in series or parallel(should be parallel, I think)?

From your description, sounds like you tried the 25w resistor in parallel...maybe try it in series?
Same with the led banks...are you wiring them in series or parallel?
Just shooting blind here, but I promise you that it can work.