Error creating relation in DataSet

[Oddball]

What on earth causes an ArgumentNullException? I've checked the spelling of my
table and column names, those are fine. The relation I created one line above this one
creates fine.

I can't continue developing this app until I work out why this is happening - and I can't
work it out :S
-- CODE--
Catalogue.Relations.Add(ADM.COLLECTION_FURNITURE_R ELATION,

Catalogue.Tables[ADM.COLLECTION_TABLE].Columns[ADM.COLLECTIONID_FIEL
D],

Catalogue.Tables[ADM.FURNITURE_TABLE].Columns[ADM.COLLECTIONID_FIELD]
,
true);
-- END CODE --

-- EXCEPTION --
[ArgumentNullException: 'column' argument cannot be null.
Parameter name: column]
System.Data.DataKey.Create(DataColumn[] columns, Int32[] sortOrders)
System.Data.DataKey..ctor(DataColumn[] columns)
System.Data.DataRelation.Create(String relationName, DataColumn[] parentColumns,
DataColumn[] childColumns, Boolean createConstraints)
System.Data.DataRelation..ctor(String relationName, DataColumn parentColumn,
DataColumn childColumn, Boolean createConstraints)
System.Data.DataRelationCollection.Add(String name, DataColumn parentColumn,
DataColumn childColumn, Boolean createConstraints)
Adquiesco2.Global.CreateCatalogueDataset(Adquiesco DatabaseManager dCon) in
d:\web design\active sites\adquiesco2\global.asax.cs:120
Adquiesco2.Global.Application_Start(Object sender, EventArgs e) in d:\web
design\active sites\adquiesco2\global.asax.cs:34
-- END EXCEPTION --
------------------------------------

Another unchecked rambeling brought to you by:

Oddball
joshua@bf#N0SP4M#wd.co.uk

[Maqsood Ahmed]

Hello,
Please answer these questions. What is ADM. Are the accessors after
the '.' properties or static variables?
Are you sure that the columns you are getting for the relation are not
null?
Maqsood Ahmed [MCP C#,SQL Server]
Kolachi Advanced Technologies
http://www.kolachi.net

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