I just recently installed a second instance of wordpress on my paid hosting server. The first site is in the home directory and works perfectly. I installed the second in a subfolder linked to a subdomain on the server. Everything seems to be working properly except that the icons and images (including visual editor icons, icons in the sidebar, ect.) do not display. I have tried a multitude of things that people have suggested to those with similar problems, but none have worked:
-viewed in different browser
-re-uploaded all wp files
-re-uploaded wp-admin/images folder
-tried changing chmod permissions through cpanel
Check your hotlink protection. I had more than one site on my hosting account, and I had enabled hotlink protection (to keep others from stealing bandwidth). The icons, even though stored in the local WP file, are still hosted under the main domain. In my case, I had not added my new domain to the list of permissible sites to access image files.
By just adding the domain to the list of permissible sites, the icons in the image editor showed up right away.