You need to use the token appropriate for the variable type in order to retrieve its value; You can't just stick the name between brackets...
This topic attempts to summarize information on tokens and variables.
The "{DATETIMEFORMAT:}" token takes a date/time variable as its first parameter, not a text variable.
You need to use the "Convert a Variable Value" action to convert the value of your text variable and store it in a date/time variable, after which you can use the "{TIME:}" token to retrieve that value if you're just looking for hours and minutes without seconds.