Plugins won't install on Eclipse

Question

I am trying to install subversive and checkstyle onto Eclipse IDE for Java Developers however the following message appears:

\"Cannot complete the install because on

Answer 1

I had the same problem, and I solved it by setting

"Contact all update sites during install to find required software"

to true.

(I used the Eclipse install manager, in Eclipse IDE for Java Developers, Version: Indigo Service Release 1 )