Thaer,
the main software requirement for using ODA is an installed OneWorld client. ODA is dependant on OW client being installed.
Other than that it should work for you.
Have you tried accessing the OW database via ODA from Access or Excel/MSQuery? If those work then its your programming that is at fault.
However I would encourage you to again try using the native ODBC or OLEDB database driver again. To deal with issues such as decimals, dates, and meaningful names just create a database view that:
1) Substitutes meaningful names for JDE aliases
2) Convert's JDE Julian dates to normal dates (search this site for technique)
3) Divides numeric fields by 10^#decimal places to properly place the decimal point.
The advantages of this approach is that it has much better performance than ODA and you have more flexibility in table joins than with ODA.
If on the other hand you are not very familiar with SQL or database programming than perhaps ODA is better for you.
Good Luck,