SQL 2000 does not support Variables within the OrderBy statement. We use NewID() for the Random Sort option but this will fail if your running SQL 2000 or a newer version in SQL 2000 compatibility mode.

The error message you'll see is:
The SELECT item identified by the ORDER BY number 6 contains a variable as part of the expression identifying a column position. Variables are only allowed when ordering by an expression referencing a column name.  

To resolve this problem, use SQL 2005 or newer, or remove this line from the Articles_GetArticles Stored Procedure: CASE @SortField WHEN 'Random' THEN NewID() END