Shwetha,
It seems that regardless of which version of the API I'm running, everything seems to be failing with this call:
$report=ReportUtils::DownloadReportWithAwql($reportQuery, null, $user, $reportFormat, $options);
$report = explode("\n", $report);
I have gone through seemingly endless trials of figuring out which part of that is causing the failure, and have ruled out the query, reportFormat, and options. I'm fairly certain it's not the user either, as no errors seem to be drawing from that call - things just fail.
Is there something I'm missing after updating, perhaps on that ReportUtils class?