How to get a seam project compiling again once it has been checked out of source control...
 
This assumes that the project being checked out is an ear deployment created using the New Seam Project Wizard. It was also using Eclipse Europa (v 3.3.2).

1) Go to File->Import..->General->Existing Projects into Workspace, browsing to the directory containing the <project>, <project>-ear, <project>-ejb and <project>-test directories and selecting all of them.
2) Once the project has imported, right click on the ejb directory and select Build Path->Configure Build Path...
3) Select targeted runtimes and New and then add a new JBoss 4.2 Runtime (which I gave the name "JBoss 4.2.3 Runtime" to match the version of the server I was using). At this point also ensure that the only JRE installed is the one you want (6.10) and make sure it is selected.
4) Check the check box next to the new runtime and click apply.
5) Remaining in the "Configure Build Path..." dialog, select Seam Settings->Installed Runtimes and select the directory containing the seam version that you are using (You may also need to change the Version). Once selected, click finish and OK.
6) Still in the "Configure Build Path..." dialog, select Java Build Path->Libraries [Tab] and (if it exists) edit the (possibly unbound) server library and select the 4.2.3 runtime added in step 1.
7) OK the "Configure Build Path..." dialog and select the servers tab in the main project window (you may have to go to the view menu to get it to appear if it doesn't already, or change the perspective to seam). Right click and select New Server->JBoss, a division of Red Hat->JBoss AS 4.2. Also select the JBoss 4.2 Runtime created in step 3 and then click Next.
8) Give the server a name such as JBoss 4.2.3 Server and click Next, in the final step add the ear project to the configured projects and click Finish.
9) Right click on the ejb directory and "configure the build path" again. This time, select server and select the server added in the previous step(s) and then click OK.
10) Right click <project>-ear/resources/<project>-ds.xml and select "Deploy to Server".
11) Right click <project>-ear and select Properties->Server and then select the server previously added and click OK.
12) Repeat step 11, but this time select <None> for the server - I know this is weird, but these are the exact steps that I took, and I got it to work Tongue out
13) Restart eclipse.