Recently I started development on Android platform. When I first installed Android sdk 2.1 through SVD Manager, I encounter a very strange error below. The major problem with this error is that it occurs after taking longer time of downloading the component. For my internet connection it took about 23 min which it requires for downloading the component. After downloading the component it renames the tool folder which causes this error to occur :

Downloading Android SDK Tools, revision 4
Installing Android SDK Tools, revision 4
Failed to rename directory E:android-sdk_r3-windowstools to E:android-sdk_r3-windowstempToolPackage.old01
-= Warning ! =-
A folder failed to be renamed or moved. On Windows this typically means that a program is using that folder (for example Windows Explorer.) Please close all running programs that may be locking the directory ‘E:android-sdk_r3-windowstools’ and try again.
Skipping ‘SDK Platform Android 2.1, API 7, revision 1′; it depends on ‘Android SDK Tools, revision 4′ which was not installed.
Downloading SDK Platform Android 2.1, API 7, revision 1

First I thought that I mistakenly opened tool folder in some other application so I started SVD manager again which took me again 23 min and after that I got the error again. Very frustrating. Since I was using windows 7 so I thing there might be some problem with windows 7. I started googling on this problem and then reviewing few ppls work around I came to know that this is typical problem with Antivirus. So when I turned off my Antivirus the error resolved. Hope my this post would definitly helps to novice you are just entering in the realm of the android development.