Could be lots of things, starting with white balance issues, reflections, light leak thru the viewfinder, really bad filter.
One very important thing to remember is that DSLR cameras have some level of IR filtering applied to them, so when you filter out everything else some of what you do allow through will never reach the sensor. This reduced level of IR light will mean that what you get from your camera will not look like other IR conversions, and you may miss out on part of the spectrum unless you convert your camera to full spectrum.
White balancing on IR photos must be done against a green source - usually a nice patch of grass. If you've never done custom white balancing then look it up and learn how to do it. If you have, replace your grey card with the green grass and have at it.
If you're shooting on a tripod I suspect you had some level of direct sunlight hitting your viewfinder during the shot as the lines seem to be light leak. If not, then I have no idea.