Upload issue with Rx/Tx connected

I have a Duemilanove atmega328. Has been working fine for developing code. I have now connected a serial LCD to the Tx pin and that works fine. The next step I added a EDE1144 keypad encoder and membrane keypad. What happens now is the arduino flags an error whae I try to upload.

"avrdude: stk500_getsync(): not in sync: resp=0x00 avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51"

If I disconnect the Rx line to the Keypad Encoder the Arduino behalves as expected (I can once again upload to it). Is there a way I can delay the Rx from reading that input until the uploading is complete?

Thanks

Why don't you just use the NewSoftSerial library for the lcd/keypad functions as you can then assign to any other two pins?

http://arduiniana.org/libraries/newsoftserial/

Lefty