Can't checkin new document using iManage COM API

masterofimages

I'm having problems checking in a new document using the iManage (COM) API. Following the sample code in the SDK documentation, I can create a new document just fine. Then I set the required profile fields (again, no problems), but when I try to set the required custom attributes I get the following error:

System.Runtime.InteropServices.COMException : [CollectionData ][Item ]Item "28" does not exist in collection
at IManage.NRTCustomAttributesClass.Item(Object Index)

Attribute 28 (IManage.AttributeID.nrCustom4) is the first of 2 required attributes in the RequiredFields collection of the document class. Any attempt to check-in the document without setting the required attributes results in the following error:

System.Runtime.InteropServices.COMException : [NRTDocument ][Checkin ]Importing new document into database : Document profile is invalid

Here is a sample of the code I am using:

' Create new iManage document and set required profile attributes
Dim newDocument As INRTDocument = document.Database.CreateDocument()
With newDocument
' Set new document security and document type to match source document
.Security.DefaultSecurity() = document.Security.DefaultSecurity
For Each acl As NRTGroupACL In document.Security.GroupACLs
.Security.GroupACLs.Add(acl.Group.Name, acl.Right)
Next

For Each acl As NRTUserACL In document.Security.UserACLs
.Security.GroupACLs.Add(acl.User.Name, acl.Right)
Next

.Author = document.Author
.Class = document.Class
.Description = description ' Use supplied description
.Operator = GetCurrentUser(.Database)
.Type = document.Type

' Set required custom attributes
For Each attribute As AttributeID In .Class.RequiredFields
.SetAttributeValueByID(attribute, document.CustomAttributes.Item(attribute)) ' <--- First exception occurs here
Next
End With

' Get a copy of the source document and check this in as the new document
document.GetCopy(checkoutLocation, GetCopyOptions.nrNativeFormat)
Dim profileErrors As Object = Nothing
newDocument.CheckIn(checkoutLocation, CheckinDisposition.nrNewDocument, CheckinOptions.nrDontKeepCheckedOut, profileErrors) ' <--- Second exception occurs here (if line of first exception commented out)

The above code is VB.NET (2005), using a generated iManage Interop assembly to access the iManage COM dll (version 7.5.0.115).

I appreciate any help on this.

Thanks,

Paul