Arduino Clone Not Working with Win7 64-bit

I picked up an Arduino clone made by BETEMCU, and I am having some mixed results. It uses a Prolific PL-2303HX USB chip. I downloaded the most recent PL-2303HX drivers (1.8.0) from prolific.com.tw. If I install on my machine at work, or my laptop at home (both running Windows 7 64-bit…one is Home edition and the other is Enterprise), the driver installs fine, and it recognizes the “Prolific USB-to-Serial Comm Port” when the board is plugged in. When I run the Arduino IDE and try to upload any sketch, it gives me the “not in sync” error. I have also tried the 1.0.3 version drivers, with the same results. Full output using “verbose” is below.

BUT, when I install and run on my Windows Server 2008 R2 (64-bit) machine, it all works just fine. Any ideas why that is, and how I might be able to resolve the issue? Thank you!

Using Port : \.\COM4

Using Programmer : arduino

Overriding Baud Rate : 115200

avrdude: Send: 0 [30] [20]

avrdude: Send: 0 [30] [20]

avrdude: Send: 0 [30] [20]

avrdude: Recv:

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

avrdude done. Thank you.