We understand that you have troubles to get a solid connection, it's necessary to determine if the issue is happening only remotely or locally too. Do you have the same issue when you connect to the Slingbox at home? If this is the case, try resetting the Slingbox to factory settings and then run the Setup on Slingbox.com.
Let us know how that works. If the issue is only remotely when you are connected to the Slingbox away, have a look at the following articles since this could be an issue with the network at home (upload speed):