php5.0.5 include() terminates script BUGBUGBUGBUG

has anyone had an issue using php5.0.5.... i seem to have a problem when my scirpt hits the include() statement it terminates the rest of the script... the script im using is a complicated login system...the script works fine online....my server is using php 4.3.1 (i was too before upgrade) and the script runs fine you can view it here http://www.phdev.net the script starts working in the ebook center section when registering... my first few lines at the start of the page and there after have the include statement... so in php 5.0.5 none of the pages appear...does anyone have anyidea???? i have altered this comment to require but still the same....the file tree seems to be in order too.... regards alex