403 errors on the public directory

Recently I began work on a fresh install of current version of OJS to replace our current install, which is very old. I am working in a shared hosted environment which allows for multiple domains in individual directories within the public_html folder. So the new install is in its own directory and domain name, while the original is in the root.

It seemed like a good way to begin work on this rather monumental task. However, the new install seems to be affecting the old install, in that any access at all to the public folder in the old install is now returning 403 errors. htaccess files with the old install have not been modified. The new install currently has no htaccess files.

Is there anything I can do, short of deleting the new install, to fix this problem?

Thanks

Update. I have deleted the new install. However the images in the public directory of the original install still fail to display. I have edited permission in the public directory to 766 for all. It has not helped the issue.