I don't understand why the code below throws an err 61 sometimes
BUSY_FILE_NAME$ = "[lcl]Busy.txt"
serial BUSY_FILE_NAME$, err = *next
if tcb(2) {
rem in case the file could not be created ...
} else {
busyFile = hfn
open lock (busyFile) BUSY_FILE_NAME$
rem this throws error 61 ???
}