Sippino avrdude: stk500_getsync(): not in sync: resp=0x00 error

Hello,

I am currently using a Sippino board to try and communicate using a simple program that outputs an incrementing count value every second. I was able to this once, and record the values from the Serial monitor.

However, two days later when i tried to upload it again, I was getting this error:

avrdude: stk500_getsync(): not in sync: resp=0x00

I used the same serial port, same board... what has happened?

Thanks for your time.