Unable to deploy same solution on different webapplication

Hi,

I have one farm having multiple web applications in sharepoint 2010.

My frient had deployed one solution having different webparts,events and jobs on 2-3 webapplications.

Now, I have created new webapplication and m trying to deploy that same solution code on my new application,but its showing error like,

"Error occurred in deployment step 'Retract Solution': Object reference not set to an instance of an object".

I tried to reract it from VS then its showing error-Object reference not set to an instance of an object.

What should I do to deploy this solution on my new webapplication.?

Anybody got this of issue before please suggest any way...

Thanks

Vyankatesh