HELP! Serpentine belt slipping off Water pump wheel!!!

[lejolierogue]

Dear enthusiast,

I encountered what might be a huge problem when I was replacing my serpentine belt.

I've a 99 Boxster with approximately 44K miles. I watched in horror as the water pump wheel wobbled as I cranked up the engine which eventually displaced the serpentine belt about half was off. I tried this several times just to make sure I installed the belt correctly.

I was probably running the car like this unknowingly which explains why my belt separated at 44K miles instead of the regular 60K miles.

Has anyone experienced this? Any idea how much this would cost to repair? Or is it a matter of tightening a bolt or two that holds the water pump wheel in place?

I also tried looking for a bolt to tighten but it seem that the nut could be on the other side/inside.

Please advice and thanks in advance.