I found the bug in "Convert.c": "Day" is a reserved name in Zorro, but "Convert.c" used it as the input parameter of ConvertTime() and as a general variable name in various other places. To solve this problem, just change all the variables named "Day" to a different name that is not a reserved name, e.g. "aDay".

I have attached the modified "Convert.c" that compiles fine.