The best resolution is to upgrade to Helpdesk 6.0 SP5. The resolution below has been implemented into the SP5 release. 

If you cannot upgrade to SP5, below is a SQL command to alter the sp_createHDDview stored procedure used for creating views. Changes to the stored procedure will allow a larger number of lookups to be added.

Using a SQL query tool like SQL Server Management Studio, connect to your SQL server for Helpdesk and execute the following SQL command against the database used for Helpdesk (usually Altiris_Incidents).

/*Start SQL code */
ALTER PROCEDURE [dbo].sp_createHDDview
      @viewname nvarchar(255),
      @tablename nvarchar(255)
As
begin
      /*
            this stored procedure will build a CREATE VIEW SQL statement and execute it using sp_executesql
            We use a tricky double string replacement to allow us to save a bunch of
            repetitive code and get around T-SQL restrictions on where @ variables can appear
      */
     
declare @createviewsql_template nvarchar(4000)
declare @cvsql nvarchar(4000)

/* drop the view if it exists */
if exists (select * from sysobjects where id = object_id(@viewname) and OBJECTPROPERTY(id, N'IsView') = 1)
begin
    set @cvsql = N'drop view ' + @viewname
    exec sp_executesql @cvsql
end

/* drop the view if it exists - drop [dbo].@viewname. */
if exists (select * from sysobjects where id = object_id('[dbo].'+@viewname) and OBJECTPROPERTY(id, N'IsView') = 1)
begin
    set @cvsql = N'drop view [dbo].' + @viewname
    exec sp_executesql @cvsql
end
/* this template for the sql to execute calls sp_executesql itself to actually create the view */
     
set @createviewsql_template =
N'         
declare @selclause nvarchar(4000)
declare @joinclause nvarchar(4000)
declare @col nvarchar(4000)
declare @join nvarchar (4000)
declare @colsql cursor

set @selclause = N''''
SET @colsql = CURSOR FAST_FORWARD
FOR
SELECT DISTINCT column_sql
FROM view_def
WHERE table_name = N''~VIEW_NAME''

OPEN @colsql

FETCH NEXT FROM @colsql into @col
WHILE @@FETCH_STATUS = 0
BEGIN
    set @selclause = @selclause + N'', '' + @col   
    FETCH NEXT FROM @colsql into @col
END
CLOSE @colsql

set @joinclause=N''''
SET @colsql = CURSOR FAST_FORWARD
FOR
SELECT DISTINCT join_sql
FROM view_def
WHERE join_sql != N''''
AND table_name = N''~VIEW_NAME''
OPEN @colsql

FETCH NEXT FROM @colsql into @join
WHILE @@FETCH_STATUS = 0
BEGIN
    set @joinclause = @joinclause + N'' '' + @join   
    FETCH NEXT FROM @colsql into @join
END
CLOSE @colsql

set @selclause = substring(@selclause,2,len(@selclause)-1)

execute (N''CREATE VIEW [dbo].~VIEW_NAME AS SELECT '' + @selclause + N'' FROM ~TABLE_NAME '' + @joinclause)
'
set @cvsql = replace(@createviewsql_template, N'~VIEW_NAME', @viewname)
set @cvsql = replace(@cvsql, N'~TABLE_NAME', @tablename)

execute sp_executesql @cvsql
end
GO
/*End SQL code */