Why? [Oracle][ODBC]Option value changed

[Sonnich]

I get this error:

Warning: odbc_exec() [function.odbc-exec]: SQL error:
[Oracle][ODBC]Option value changed., SQL state 01S02 in SQLExecDirect
in
C:\Inetpub\wwwroot\JOTIntranet\Modules\supplyservi ces\supplyservices_updateditems.php
on line 435

Warning: odbc_fetch_row(): supplied argument is not a valid ODBC result
resource in
C:\Inetpub\wwwroot\JOTIntranet\Modules\supplyservi ces\supplyservices_updateditems.php
on line 437

Here:
$result=odbc_exec($conn, $sql2);
$k=0;
while(odbc_fetch_row($result))

But only when I select a lot of data (say 2-3 days of data no problem,
but one week - I get this. 2 weeks and I get this a number of times.
The SQL2 is just a normal select blahblabhalll.

Can anyone give a hint?

BR
Sonnich