Oracle Database Discussions

Hi,

Each time I attempt to use SQLPLUS to connect to my db, I receive:

ERROR:
ORA-12537: TNS:connection closed

The listener.log contains these entries:

TNS-12525: TNS:listener has not received client's request in time allowed
TNS-12535: TNS:operation timed out
TNS-12606: TNS: Application timeout occurred
06-JAN-2012 17:09:51 * <unknown connect data> * (ADDRESS=(PROTOCOL=tcp)(HOST=172.19.1.54)(PORT=50067)) * establish * <unknown sid> * 12525
TNS-12525: TNS:listener has not received client's request in time allowed
TNS-12535: TNS:operation timed out
TNS-12606: TNS: Application timeout occurred
06-JAN-2012 17:10:23 * ping * 0
06-JAN-2012 17:10:23 * (CONNECT_DATA=(CID=(PROGRAM=)(HOST=)(USER=SYSTEM))(COMMAND=status)(ARGUMENTS=64)(SERVICE=(ADDRESS=(PROTOCOL=TCP)(HOST=SERVER01.domain.local)(PORT=1521)))(VERSION=169870336)) * status * 0
06-JAN-2012 17:10:54 * <unknown connect data> * (ADDRESS=(PROTOCOL=tcp)(HOST=172.19.1.54)(PORT=50074)) * establish * <unknown sid> * 12525
TNS-12525: TNS:listener has not received client's request in time allowed
TNS-12535: TNS:operation timed out
TNS-12606: TNS: Application timeout occurred

Earlier today, I could log in without problems. I had been experiencing this error on my first attempt to login, but if I immediately attempted a second connection, would be logged in. Now, I cannot connect. Nothing has changed otherwise. Does anyone have any idea what may be causing this? I am using the sql plus command prompt, on a Windows Server 2008 R2 Service Pack 1. Oracle 10.2.0.4 Production, 64-bit.

Thank you,
Jesse