It's possible that your computer is not stable enough to compute a stage 1 for that many days in a row without error.

I'm not saying this is the case but it's one possibility.

Also you can try,

168451,2,1116,1,4294967295,1,0

I think this works as well (running stage one only).

Your other option is to break the P-1 into stages.

Not sure of the exact way to do it but...

168451,2,1116,1,1000000000,1,0

168451,2,1116,1,2000000000-1000000000,1,0
etc...