>Hi everybody,
>
>We're having some strange errors. I've checked the error log and found that biz object post save hook method failed with Invalid Key Length message. I've checked help on this error, but it's still not clear to me what may have cause this problem. AFAIK all our indexes are created with machine collating sequence.
>
>Do you have experience with this problem and can you give some advices?
>
>Thanks in advance.

From HELP:

Maximum # of bytes per index key in a non-compact index - 100 
Maximum # of bytes per index key in a compact index     - 240 

If the collating sequence is set to MACHINE, each character uses one byte. If the collating sequence is not set to MACHINE, each character uses two bytes. If the indexed field supports null values, one additional byte is used in the index key. Note that non-machine indexes are always compact

So check what is the expression of that index and if it exceed the limitation