Its probably because some other application is using the port 2638.
Determine which process is using port 2638 by using the "netstat -ab > c:\ports.txt" command
Stop the service that is using 2638 currently. Preferrably through the Services Panel. (Start->Run..->services.msc).
Try installing SPC again it should work. If it does not work then you can also change the embedded database port to 2639 by doing the following.
Stop the embedded database and the SPC service form services.msc
Browse to HKEY_LOCAL_MACHINE\system\currentcontrolset\services\asanys_sem5\parameters
Double-click on Parameter DWORD Value and change the 2638 value at the end of the string to a port you have determined to be free such as 2639.
Open C:\Program Files\Symantec\Symantec Endpoint Protection Manager\tomcat\conf\server.xml (default location) with Notepad.
Change the line which reads <value>jdbc:sybae:Tds:localhost:2638/?JCONNECT_VERSION=5</value> and change 2638 to reflect the new port number.
Restart the embedded database and the SPC service form services.msc