There are a couple of things I can think of.

Try increasing the preamble bytes $55. So, you send $55,$55,$55,$55,$55,$66,[data]
Try flagging the capture of qualifier in receive module to the LCD. So, you know if it is being captured correctly.
Perhaps the most important to me. Try keeping the transmitter on continuously till you get the receive part working correctly. Maybe the switching on/off of the transmitter is causing the receiver to go crazy.