CF8 - All cfm pages (including administrator) result in 503 errors

I have an old CF8 server, running as J2EE under JRUN, that's been running fine for several years.

Last night, I was in the adminstrator revising a sandbox and RDS. Settings were saved successfully, and I restarted the service. And now *all* CFM pages (including /CFIDE/administrator) simply return a white page. When analyzing the request with Firebug, it reports a 503 server error.

I'm running under Windows Server 2003, SP1, Standard.

I'm unsure of the exact CF server version, since I can't get into the administrator to check, but I believe it has at least one service pack installed.

The cfusion-out.log has the following:

12/01 09:05:09 user CFInternalServlet: init

12/01 09:05:09 user failed to load: flex.server.j2ee.filemanager.FileManagerServlet

12/01 09:05:09 error Could not pre-load servlet: CFInternalServlet

[1]java.lang.NullPointerException

    at flex.server.j2ee.filemanager.FileManager.getFile(FileManager.java:32)...

           etc

[0]javax.servlet.ServletException

    at coldfusion.bootstrap.ClassloaderHelper.initServletClass(ClassloaderHelper.java:102)...

           etc

java.security.AccessControlException: access denied (java.io.FilePermission \C:\JRun4\servers\cfusion\cfusion-ear\cfusion-war\WEB-INF\flex\jars\flex-webtier.jar read)

    at java.security.AccessControlContext.checkPermission(AccessControlContext.java:323)...

           etc

12/01 09:05:09 user failed to load: flex.webtier.server.j2ee.filemanager.FileManagerServlet

12/01 09:05:09 error Could not pre-load servlet: FlexInternalServlet

[1]java.security.AccessControlException: access denied (java.io.FilePermission \C:\JRun4\servers\cfusion\cfusion-ear\cfusion-war\WEB-INF\flex\jars\flex-webtier.jar read)

    at java.security.AccessControlContext.checkPermission(AccessControlContext.java:323)...

           etc

(I can certainly provide more detailed logs if needed)

I'm figuring the "access denied" errors have something to do with it, since I was, indeed, adjusting sandbox security in the administrator right before I began experiencing the 503 errors.

But I'm unsure how to solve, now that I can't even get back into the administrator.

Any way to get this instance back up and running, short of a reinstall?

Thanks in advance!

-Carl