DB Look up...... fed up

Folks!..

I have tried a lot to retrive data from document using Db Lookup, but i am failing to retrive…

Here is my requirement:

1st form : 3 feilds : “name of the company”

                          "location"

                          "phone no"

In above form i will add Name, loction & Phone no of the Company & i will create view for the same…

Ex:

Company name : XYZ

Loction : ABC

Phone No: 123

Now in 2nd form : 3 feilds : “name of the company”

                                     "location"

                                     "phone no"

I have created Dailog list for “name of the company” using Db Column(used view to retrive data)

If i select “Comapny name” in 2nd form, automatically “Location” & “Phone no” should appear.

For above i used below formula

@DbLookup(“”:“NoCache”; “”; “View”; “Key”; column no);

But i getting following error

“Feild location: Entry not found in index or view’s index not build”

Please help me in this regard, & i want know “What is Key word”

In above example which is key word???

Thanks

Vijay