I had a problem with my ITB last January. It was at the outside of my knees. I used a stretch from Running Well and that cleared it up a treat. Use that now pre-runs and I've *touches wood* not had a problem since.
I'd agree with AG about the long run. Took my PB from 20:52 to 20:20 in the space of five weeks during recent marathon training and I predominantly attribute it to the much longer runs that I had been doing in preparation. I'd also suggest adding some interval and tempo running to your schedule - perhaps replace one of your HIIT sessions on the bike with alternating weeks of a tempo session and an interval session.