Retrive after resolve task fails because of wrong resolve configuration.
If you have set on your ivy.xml a different configuration than the configuration in the retrieve after resolve textfield,
the retrieve step will fail because no resolve was run for selected configuration.
How to reproduce:
Right click on your ivy.xml classpath and change the configuration to master. Then go to Window-> Preferences->Ivy check "Do retrieve after resolve"
and enter "runtime" in configuration text box. Close your eclipse. Remove your .ivy2 cache file. Startup your eclipse and you will get the error.
Merge the configuration needed for classpath setting and configurations needed by retrieve before doing resolve.