When attempting to execute a statement that queries any of
the Solid System Tables I get a "Document contains no data."
error message.

The following query will reproduce the error:

$result = Solid_Exec("select * from sys_tables");

I think it has something to do with results retrieved from
System Views under Solid.

I have executed this query under the solsql command line
utility with the same user account I am using in my script,
and received the expected normal query results (IE: it works
under solsql, but in PHP it breaks).