I am sorry to hear that you are experiencing this problem.
The error message is not telling you that the driver is missing, but it cannot open or find the unit. It is possible that the laptop is not able to power the PC via the serial port. This can be checked by testing the voltage in Pins 4, 7 and 5 where the voltage should be -7volts, +7 volts and gnd respectively.
Start Picolog up with the unit connected then disconnect the serial cable from the TC-08 and test the voltage with a metre. If the voltage is close or below this then the likelyhood is that the voltage is dropping and the TC-08 cannot be powered. If this is the case please send a email to:
requesting battery diagram for serial products.