I had similar problems in Durlags - I could detect traps but not disable them. I went away and bought a few potions that would allow me to disble some of the traps and I used a comination of spells and potions to overcome the effects of those that I couldnt disarm.

And yes, I did manage to finish the tower in this way.

I passed the four traps (5 hours ago :) by running each character on the left side of the corridor. The last of the traps is the widest but staying on left is ok. Imoen couldn't disarm any of these...

You can also pick up Safana at the one of 3 sword coast areas (Ibe believed the one with the cave were the tome of constitution lies. If your main char is above level 6 or something, she will be in a similar level. She then has a pecentage of 90% for disarming the traps....

Although offcourse, this will force you to - or add another person to your party - or disbanning an other for her.

Or just use those potions of preception.