Have him try using ReIndex in Database > Housekeeping.
The second reason for this kind of error is a result of faulty hardware. You can set PostgreSQL to ignore these errors by clicking Start --> Programs --> PostgreSQL --> Configuration Files --> Edit postgresql.conf. In the configuration file that appears, go to the bottom of the file and add the text “zero_damaged_pages = on” on a new line and then save and close the file. Click Start --> Programs --> PostgreSQL --> Reload Configuration and PostgreSQL will ignore the damaged data. If you continue to have problems with that hard drive, you should consider replacing it.
If that doesn't help please
report the problem so that we can see the full error in the log file.