When I try to run my flash builder project, or clean it from within Flash builder I get the error: "Building Workspace" has encountered a problem. Errors occurred during the build. Errors running builder "compiler" on project "STAR". java.lang.NullPointerException. I have read the responses to similar questions, and when I try switching the workspace to where the project files actually are, when FB opens again, no files are showing up. When I switch the workspace back to "Adobe Flash Builder 4.7" when FB opens up, all my files are there but I get the null pointer error. There had originally been a project in the Adobe Flash Builder 4.7 folder, but I have been working from another folder for the past 10 months. Please tell me how to resolve this. Thanks!