How to do debugging

Guys,

I am new to support environment here, i am getting a system generated error while doing the delivery.

Error:

"no contract could be found valid on XXXXXXX Plant XXXX Sloc 0000 Val type UT Mat.no. XXXXXXXXX Sales HT CA & MOT"

I know that this is pointing to a table entry that is missing in the system, I don't have any idea what table entry that is missing, how can i go into debugging mode to find out what entry is missing that is throwing this error.

Guys if you have any step by step process of debugging could you send me please.

srinir2009 at g mail com