@coherence*web, Can't login admin console by NullPointerException at weblogic.servlet.internal.session.CoherenceWebSessionContextImpl.getSessionInterna

Problem：
　　After out of memory at coherence,
I started the cache server and weblogic admin server.
When I accessed the admin console following error occured and can't
login.

Log:
<2011/07/31 0時36分53秒 JST> <Error> <HTTP> <BEA-101020>
<[ServletContext@50606836[app:consoleapp module:console path:/c
onsole spec-version:2.5]]サーブレットは例外により失敗しました
java.lang.NullPointerException
at
weblogic.servlet.internal.session.CoherenceWebSessionContextImpl.getSessionInternal(CoherenceWebSessionContex
tImpl.java:516)
at
weblogic.servlet.internal.ServletRequestImpl$SessionHelper.updateSessionId(ServletRequestImpl.java:2978)
at
weblogic.servlet.security.internal.SecurityModule.generateNewSession(SecurityModule.java:318)
at
weblogic.servlet.security.internal.SecurityModule.login(SecurityModule.java:305)
at
weblogic.servlet.security.internal.FormSecurityModule.processJSecurityCheck(FormSecurityModule.java:302)
Truncated. see log file for complete stacktrace
>