cannot install Google plugin in Eclipse

Question

I want to install Google plugin, GAE and GWT on Eclipse i tried in different ways by trying to install all at once and only one at a time but i get this error

Cannot complete the install because one or more required items could not be found.
  Software being installed: Google Web Toolkit SDK 2.3.0 2.3.0.r36v201105191508 (com.google.gwt.eclipse.sdkbundle.e36.feature.feature.group 2.3.0.r36v201105191508)
  Missing requirement: Google Plugin for Eclipse 3.6 2.3.2.r36v201106211634 (com.google.gdt.eclipse.suite.e36.feature.feature.group 2.3.2.r36v201106211634) requires 'org.eclipse.pde.core 0.0.0' but it could not be found

i could install Android without any trouble. can anybody help me to solve this?

Thanks !!!

EDIT : i am using Eclipse 3.6 - Helios

Answer 1

I had this problem as well, and neither running as administrator nor changing the eclipse directory permissions fixed the issue for me.

Eventually, I discovered that the Eclipse download site (http://download.eclipse.org/releases/juno) was disabled in my "Available Software Sites" preferences. Enabling it solved the issue for me.

Answer 2

I got same problem and solved by launching Eclipse as administrator. I post this for people who face this error in future.

Firstly I changed permissions on the directory where I put Eclipse as CobaltBlue suggest but it didn't work. Next I launched Eclipse as administrator and tried again, then installation is completed!

I'm not sure it is necessary to change the access permission of the directory of Eclipse.

I am using Eclipse Juno and OS is windows 7.