Help! LED turn signal problem on 2001 Accent GS

I wanted to convert the rear turn signals on my 2001 Accent GS to LEDs, so I ordered these:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&sspagename=ADME%3AB%3AEOIBSAA%3AUS%3A11&viewitem=&item=280119160634

I installed them, and they started to blink too fast, so then I ordered these 6 Ohm, 50 Watt resistors:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&viewitem=&item=280113330403

Those resistors failed to solve the problem, so what could be the issue here?  Thanks in advance!