If you are using Grameen Phone modem and if this modem made by HUAWEI (be sure, open the modem and see the sticker of company).
Actually your modem containing old version software thats why its not able to perform video call. Lets I'm telling you a latest software that is able to make your modem smart and able to perform 3G call I mean Video Call, Voice call, SMS, MMS and other services.
contact me wasiul99@gmail.com for doing it by me(if you can't)
Here is address of HUAWEI latest version Software named Mobile Partner. Simply download it, install it in your PC or laptop. In the installing step you need to follow some instruction. Read How to install HUAWEI software (Mobile Partner) to make Video Call using any SIM.
Download Huawei Mobile Partner 23.009.09.01.983 with video call
also read How to make a video call using GP /TeleTalk sim and HUAWEI modem
also read How to make a video call using GP sim and Grameen Phone modem
also read How to make a video call using GP sim and TeleTalk modem
also Read How to make Video Call using Huawei modem with any SIM.
Update: 18.Dec.14