Damage Reduction Stacking

How does damage reduction stacking in Guild Wars work?

Can I use the new Sunspear Paragon PvE Only Skill, "There's Nothing To Fear!" with a rank of 10 and combine it with a 14 Leadership "They're On Fire!" and expect to recieve a 56.1% Damage reduction from enemies who are suffering from burning?

Also, is there a cap on damage reduction? If a character has Life Barrier, "Incoming!", "There's Nothing To Fear!", and "They're On Fire!" on them, are they going to be taking virtually no damage or does it cap out somewhere around 50% or 60% reduced?

I think you'll have 56.45% damage reduction.

First you have 35% damage reduction, so you'll have 65 out of 100 damage left.
Then you have 33% damage reduction, leaving 43.55 out of the 100 damage.
The amount reduced is 56.45 damage, or 56.45%.

I don't think there's a cap to damage reduction.

Another matter to keep in mind is that flat damage reduction (ex. -2 while enchanted or the LB title bonus) is applied before any multiplicative operations.