That's true. Converting original test to the following, works ok and doesn't need an explicit prior conversion to long values:
If (status = 0) And (oday.CompareTo(B4XPages.MainPage.AppGlobals.TestDay)>=0) Then
Maybe a warning like "operator not applicable to string type" or something like that could be useful.
Anyway, now the error message is clearer to me. It means ("since
>= operator applies to numbers and operands aren't, than here its is your error.."