Redeploy Solution to SharePoint 2007 using STSADM

So I have used the following command to deploy a solution to SharePoint as I am a new commer to SharePoint developement.

stsadm -o addsolution -filename Demo.wsp

I used WSPBuilder to build the wsp file which just contains one web part. What do I do deploy the new wsp file. When I try using the same command above I get the error.

a solution with the same name "Demo.wsp" 开发者_JS百科or id "blahblah" already exists in the solution store

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Use stsadm -o upgradesolution -filename <localwsp> -name <solutionname> -- but remember that the solutionid must be the same for both the new and the current WSPs (this is normally the case unless you're doing something a bit weird.)

-Oisin