Glen, why are you doing all that?
The problem is almost certainly that the customer PC is configured to show dates differently form you development machine. Since you are using Convert.ToString it will use the current machine settings to configure the string it returns.
Use specific formats if that is what you want:
DateTime now = DateTime.Now;
string date = now.ToString("dd/MM/yyyy");
string time = now.ToString("HH:mm:ss");
There is a list of all the formatting codes here: Formatting a DateTime for display - format string description