W32Time Error Event ID:48

Possible reason is you have problem about connecting to time server or time server is experiencing diffuculties.

List of time servers is available at ;
http://support.microsoft.com/kb/262680

After choosing time server follow the steps below;

net stop w32time
w32tm /unregister
w32tm /register
net time /setsntp:TimeServerIPNumber
net start w32time

If you want to use a FQDN instead of the IP address as time server, add ",0x1" at the end of the net time command

net time /setsntp:time-a.nist.gov,0x1