stacey11,
Can you give us some more information on this?
1. Can you clarify if the web application is already deployed to the server? Can you go to the deployment location and check if it is already existing there? You can also verify that from the servers admin console.
2. Is you web application created using MyEclipse?
3. Are there any errors logged in the log file located at workpsace dir > .metadata > .log?
4. If you create a new web application and try to deploy it to the server, does the issue persist?