Yes, but you've given us insufficient info to be sure. However, that's one of two (obvious ... and who knows how many non-obvious) possibilities:

1. "some error in the code...."
2. using == instead of eq for a non-numeric comparison

If your check (via Mark I eyeball, debug, print statements, etc) shows 2 is NOT the issue, then yes, posting some code would allow us to be more helpful. But, before posting, reduce your code to a minimal, runable example. Then be sure to also post at least a (small) sample of the data (perhaps as comma-delimited or tab-separated text).

If you are using the latest version of Spreadsheet::ParseExcel then the code giving the warning is as follows:

        ...
        # Print Gridlines
        if ( $oWkS->{PrintGrid} == 1 ) {
            $oWrS->hide_gridlines(0);
        }
        ...
[download]

The PrintGrid option should be set to a default value on creation but perhaps there is a bug somewhere.

If you like you can submit a bug report here. Follow the instructions on that page and submit the Excel file that you are having issues with. It won't be possible to debug it without the Excel file.

Alternatively, you can just ignore the warning (mentally or programmatically) if it doesn't affect the end result.

--
John.