Programmer not responding

I have an odd problem. While using the arduino pro mini sparkfun programmer, Sometime it will work perfectly and not give me any problems. But, occasionally and at random it will say "programmer not responding". I'm not sure why this is happening does anyone have any suggestions?

Probably not getting/recognising the DTR reset pulse at the right time - try pressing the reset button by hand just after starting download.

HMMM that didnt work. any oother suggestions