Daal,
There are a few things that could be causing this. This is based on the tax treaty the US has with his specific country to pay his portion of taxes, maximum 30% withholding on dividend and interest income to the account. I would want to ensure that TEFRA issues were resolved. If you can PM your name I will be able to confirm whether its a TEFRA issue. Also, this may be a requirement of the country you are from and the fund you are invested in. Please also include the name of the funds you are invested in and the country you are from. IB and MB follow the same rules so it could potentially be the difference in the fund you are invested in. With this information I will be able to resolve or at least explain why the withholding.
Regards,
Steve