Course restore hung on Moodle 2.9

We have just upgraded our Moodle 2.6 to Moodle 2.9.  The backups run just fine.  But we cannot restore any courses.  It hung.

We did a manual backup with Moodle 2.9 (just to make sure) and any attempts to restore it would result in Moodle hung.  Running SQL tracer, we see that the follow SQL query is being run "UPDATE #mdl_backup_files_temp SET ....." and it is suspended.  We also noticed that the table temp table, mdl_backup_files_temp, really doesn't exit.  Instead we have temp table of the name, mdl_backup_files_temp_________________________...

Our environment is:

IIS 7 on windows server 2008

PHP 5.6.8

MSSQL driver 3.2

SQL server 2008

Thanks.

note that we just switch from freedts to MSSQL driver as the freedts driver is quite buggy,