If trying to run a report but receiving a Cannot Execute Report error as below, the first thing you probably would think of checking is your regional settings and making sure you have the same date/time format as the reporting server.  And, this may well solve the issue, however, it may also not.  A less obvious setting to check is the Short Date Format and this is a very important setting, if the short date format is different on the computer running the report compared to the reporting server then this error will continue to appear.  It is definately worth checking as just because your date/time format is correct, doesn't guarantee your short date format is correct.

Cannot execute report

To check your short date format (on Windows Server 2003) go to Control Panel and select Regional and Language Options then click Customize on the Regional Options tab.  This will open a new window where you can select the Date tab and check the short date dormat and alter as necessary.