This is a member of the Viber R&D Team!
datdaigia- Viber is not completely supported with Android tablets. Therefore, we unfortunately will not be able to completely resolve tablet issues for you.
The new version, 2.2, for Android will be available in the Android Market for your upgrade shortly. Please upgrade to this version when available, it might be more stable on your device.
If anyone has any questions/suggestions for Viber, please feel free to let us know, and we will address them shortly.
An official representative of Viber Media (Viber app.)