Could you please tell us exactly what is in (lcFile)? There is a slight chance that your lcFile does not have the right info in it.
Generally speaking, if it works in the Command window it will work in code. While in debug mode, and the command window is open, try the exact same statement with the lcFile variable. If it works, I would be surprised. At this time figure out exactly what is in lcFile. Does the contents of lcFile have a directory in it? Does the directory have spaces? e.g. "c:\Program Files"
Is the lcFile declared as LOCAL? If not it could be changing somewhere else (from personal experience, I would rather not talk about at this time. {sniff})
APPEND FROM (lcFile) DELIMITED WITH TAB
APPEND FROM &lcFile DELIMITED WITH TAB
Hope this helps in the search.