I found a reference to this error being caused when your html code files are marked with the read-only attribute. The html splitter is part of the run-time system that parses your html files and splits lines that are too long into smaller lines that can be handled by the checker.

From development (this was quite a while ago)

The HTML file being included in a COBOL Source cannot be marked with READ-ONLY attribute.  This is because if any line in the HTML file is too long to be processed by the checker, it will be modified by the HTML Splitter before feeding into the checker.

Thus it has to be a writeable file.

If it is not writeable then the HTML Splitter will generate an error message.

So any HTML file being included in the COBOL source is expected to be writeable.

Make sure that you remove the read-only attribute from the files, either by using Windows Explorer or the attrib -r command from the command line.

Thanks.