This may be a permissions problem. Perform the sequence below, then after it reboots, open UberSocial, select 'options' from the menu, then click 'next' and click 'verify account'.
1. Go to the options icon on your blackberry (small wrench icon)
2.a. On new devices go to options -> Applications -> UberSocial
2.b. On older devices go to options -> Advanced Options -> Applications -> UberSocial
3. Set permissions to 'allow' and save the settings.
4. Remove and reinsert your battery in order to do a full device reset.
If this doesn't work, select 'options' from the menu, then select 'network options' and make sure the setting is on AUTO. If it wasn't on AUTO, switch it to AUTO, then save the settings, then select 'options' again from the menu, click 'next' and then click 'verify account'.
If this doesn't work use 'feedback' from the menu and tell me exactly what the error message says that comes up when clicking 'verify account'. Also tell us if your device is configured on a corporate BlackBerry Enterprise Server (BES), or if you subscribe to a BlackBerry Internet data plan.