If you get this problem, there is a quick fix for it.
Go to your windows services (Type Services.msc at wundows run), check the SharePoint Timer Services.
There would be 2 possible solutions.
1)You will noticed it will be stopped, start the service. If you have changed the SharePoint service password, you have to provide the password, else it will start.
2) The user you have defined in this doesnt have the write more. Might be some rights has been provoked from the user defined in the time service.
Now go back to the farm solutions SharePoint Central Administration, you will notice that now it has been done.
We faced this problem, when we changed the SharePoint service password. And then the solution retracting got stuck.