Did you run the TLServer? TLServer must be running in order to use TRiLOGI for monitoring function or to use ExcelLink.
First of all you need to establish that communication setup is OK in the TLServer by typing commands such as "IR*" in the command box and see if the PLC returns a response "IRnn*" where nn is the ID number. If not, check the comm port settings (e.g. COM1, COM2, baud rate, etc). When you can communication with the PLC you can then run the TRiLOGI software which will try to communicate with the TLServer. You will then need to supply the user name and password (there is a default usename: "samples" with no password) and then you should be able to communicate with the PLC.