There is a critical bugfix version of mydatamart available here
http://dhis2.com/download/mydatamart.exe. A dilligent user has
discovered a monthly equivalent of the year 2000 bug. The month
numbers 01,02, 03 etc were for some arcane historical reason being
treated as octal (base 8). So month 08 exposed a breaking problem.
This error is fixed in the version linked above.