new user needs help with lookup tables

I am writing a small database program that uses look up combo boxes to
display a refence number on a diffenrent table. When some one picks a
ref number I want to be able to display certain fields from the look up
table (but save them to the master database)that correspond to the ref
number eg name age ect. In total there will be about 6 of these lookup
boxes. I did try to use a normal dbedit in read only mode set to the
lookup database and this worked fine then started to display a index out
of range error.

Whats the best way to solve this problem?