Chimpegration Classic (along with Importacular) assumes that if you are using a US database, then your date and time formats will be in US format. Likewise for Canadian and UK. (How do I determine which database I am using?)
If your Windows format differs from the standard it is possible to adjust the format that Chimpegration Classic expects.
In 4.7 and above there is a new advanced setting to decide the region settings. If you press on the Z logo:
This brings up the about box. Then press the region settings option.
This brings up the following box which is similar to the Windows region settings. If you then select the format that matches your Windows format, it should override the existing formatting. This will take effect after restarting Chimpegration Classic.