Description:
------------
I executed mssql_query("...", $db, 50). The result was empty (no rows returned), and there was a read from 0x00000000 when (I think) mssql_fetch_assoc() executed. 

Reproduce code:
---------------
I had no time to record the exact code, but it was something like this:

$q=mssql_query("select * from table", $db, 50);
do {
    while ($row=mssql_fetch_assoc($q)) {
        ...
    }
} while (mssql_fetch_batch($q)>0);

the table was empty. I then prepended

if (mssql_num_rows($q)>0)

and everything was fine.

Expected result:
----------------
nothing, the table was empty :)

Actual result:
--------------
a crash because of reading 0x00000000