The tape won't effect the overall functionality of the digitiser, it is probably there as an identifier for the supplier or other identifying purposes. There are three things that could of happened.
One - You have not connected the Digitiser correctly to the logic board
Two - You could have damaged the digitiser ribbon upon installation
Three - The Digitiser you have purchased is faulty
One -Unscrew the EMI plate that covers the LCD/Digitiser connections at the top (shown below) and make sure all of the connections have been made and are secure.
Two - Now to make sure that your digitiser has not been damaged you are going to need to disassemble the iPhone and take the screen off. Take a look at these connections here to see if any damage has occurred.
Three - If all of the above options have passed and nothing appears to be wrong visually, then the digitiser might just be faulty and you will require a replacement. Contact your supplier to organise a replacement. Its always good to take a photo/video of the issue as proof of the fault.
Hope this helps :D