How to deploy plugin

I have already published nopcommerce through visual studio web deploy.
Now I made some changes in code and add a plugin also on my local Host visual studio. Now when I published through visual studio same way as before it will ask installation again. And when I entered same information which I entered before it is showing error
"Setup failed: Sequence contains more than one element".
Any body help me please I want to deploy the only changes which I have made on my local Host visual studio.
Can I deploy the only web pages which I have changed in visual studio?

naveen007786 wrote:

This exception is caused by trying to install to a database that has already been installed.
To use an existing database, you only need to copy the Settings.txt file to the App_Data folder before you start the application.

RE: "...need to copy the Settings.txt file to the App_Data folder"

Not exactly.  You need to "preserve" the production Settings.txt and InstalledPlugins.txt files that are in the production App_Data folder.  You don't want to have VS overwrite them.  In Visual Studio, make sure those files are not set to "Copy".  In any case, before you publish, you should back them up just in case.

New York wrote:

Thanks to correcting me!!

thanks for the help..