why is it when i install flashget, my antispyware said that there is a spyware/adware on the flashget …?

Flashget is one of those “grey area” programs when it comes to whether or not it is spyware.
Some anti-spyware vendors consider Flashget to be a low level risk form of spyware, many others don’t.

One anti-spyware vendor says this about FlashGet:

“Spyware Information: FlashGet
This is a Browser Helper Object (BHO). BHO’s connect to Internet Explorer while it’s running, and share information. BHO’s were originally designed to allow Internet Explorer to handle new types of data and to offer new features not originally designed into the product (like search toolbars, for example). But because BHO’s have access to all the information about the web sites that you visit (and because BHO’s run on your computer and could potentially do anything they want), they have been used by advertising companies and others to track you online.

Size: 1,274,880 bytes
Threat level: Low (more info…)
Detections: 20,156 this month: 11
Author: AmazeSoft
Others by this author: JetCar
Appeared: February, 2004″

http://www.tenebril.com/src/info.php?id=107588427

Ultimately, YOU must make the decision if Flashget is spyware on not. Read the EULA carefully, don’t just blindly check “I Accept”. Google “Flashget” and see what others are saying.

If you, yourself, are comfortable with any information the program may “phone-home” with; the keep the program.

If you are not comfortable with it, then uninstall Flashget and find an alternative.

Good luck.