OK, if the OJS parts of the page look OK, it's probably not a PHP error message. It might be file permissions or an HTML problem. Look at the source XHTML generated on the article's page and see if its HTML is included at all; if it is, you might need to correct the article HTML. If it's not, use the Journal Manager's Files Browser to find the article's HTML and see if you can access it that way. If not, it's likely a file permission problem.
Open Journal Systems Team
Don't miss the First International PKP Scholarly Publishing Conference
July 11 - 13, 2007, Vancouver, BC, Canada