You have downloaded and installed Java version 1.5 while installing the Symantec Endpoint Protection Manager (SEPM) console. You have updated it to one of the releases of Java 1.6 and you are now not able to login to the console remotely.
SEPM remote console is not compatible with some versions of Java 1.6. Sun Microsystems has released Java 1.6 update 4, 5, 6 and 7 which resolves the compatibility problems faced earlier, wherein the automatic update of the Java Virtual Machine from version 1.5 to version 1.6 caused the remote SEPM consoles to give Login Errors. Ensure that your remote SEPM console is at a minimum version of 11.0.1000 (MR1).
Note: Version 1.6.10 and 1.6.11 are again not compatible with the remote SEPM java console, please do not upgrade to Java 6 beyond update 7: