Error: java.lang.nullpointerexception

I have got the error "java.lang.nullpointerexception" when I tried to install Oracle 11g client. It was caused due to unavilability of  folder to write install logs in admin mode.

In my case, it was looking for my home directory to write log files.

Solution:

Run cmd prompt in admin mode
map home directory with teh follwoing command
net use x: \\servername\share\home_folder

Then,
Run Oracle client setup in admin mode.

Have a nice day!

Remote logins disabled after server reboot

This was caused by many reasons. One of the reason was  that when the elected zone data collector server was rebooted, servers that rebooted at that time, couldn't contact the zone master and had logins disabled.
Some one disbale logins manually through Citrix console.

It happens when LHC corrupted.

Solution:

Follow one of these solutions based on your findings

1. Make a preferred zone master and make it its reboot schedule in other time than remaining servers.

2. Enable logins through Citrix console

3. Recreate LHC

4. Create a schedule task with
SCHTASKS /create /tn "OpenCitrixLogon" /TR "cmd /c change logon /enable" /SC daily /RU "NT Authority\System" /ST 06:00 /F

5. Change Registry key through a batch file after reboot. You can also run it through a scheduled task.

HKLM\System\CurrentControlSet\Control\Terminal Server

DWORD = fDenyTSConnections
Value = 0
6. Follow this article
http://support.citrix.com/article/CTX134641

Have a nce day!