Meaning?!

[DJ_Shocker]

I'm encountering this error:

0: attempt to get length of field '?' ( a nil value ) 

now the line 0 is very helpful on top of the fact the "?"

What the heck does this mean and what can I look for to resolve it?

[WhoAmI]

Are you using string.len or sth? Show us the code.

[DJ_Shocker]

I figured out it was a MySQL issue when it was trying to get the last set shop ID.

Thanks WhoAmI. and no i wasn't using string.len or sth, but I do appreciate the response.