problem with connecting to arduino

Hi, I have Arduino Duemilanove and everything works but now when i want to upload my code with different computer give me error.

Binary sketch size: 990 bytes (of a 30720 byte maximum) avrdude: stk500_getsync(): not in sync: resp=0x00 avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

Before i still could upload code form first computer but from today i cant??

Where i problem?? I tried changing ports.

Thanks

One of the most often problem. You haven't used the right port address. Go to 'Tools' on the Arduino software window and choose for Serial Ports another port. Means one of them which are listed. Mainly higher than COM4.

i changed port and now works on both computers, thanks

Mainly higher than COM4.

That is weird. My Deumilanove always connects at COM3, my Prominis always connect at COM7. They have different connector types, so use different cables. Always wondered if it was the cable making the difference or something different about the way the FTDI chips are set up. Can't tell with these molded cables if there's some active elecrtonics in them.

before it was connected to COM3, now it is on COM5.