how did you hook up the lights? did you just wire tham into the fuse for the directionals or did you wire them from the directional lights themself? the two lights work on different voltages. (im guessing they are street glow or something compareble) the street glow lights work on a 12v current while the directional bulbs work on like a 6v. you cant just wire them strait in like that because it will either blow out the street glow lights or they will demend more power and blow out the other bulbs. i did the same thing in my car only mine are under the front bumper and they are yellow lights..i looked for lights with a smaller voltage that was the same as the directionals. and i also have a red light under my rear bumper that lights with my brakes. i just ran that through the fuse box for voltage and ran a switch to a brake sensor.
you cant just wire things in...you gotta do some research first. try to take out the blacklights then check the fuse and the bulbs. im guesing that once you take out the blacklight they should work..if not, then you might have shorted something out which would leave you with no blinkers for the rest of your life...unless you get a new fuseboard..which if you cant handle hooking up lights i doubt you will be able to hook up a new fuse box.
but good luck man.