folder missing from Apache index

[barnabas]

I am using xampp-lite version 1.7.2 for windows, Vista with Firefox 3.6.3.
I copied a zip file into a folder under my xampp directory, unzipped the file and was able to see all of the files from the zip archive.
I then made several changes to some of the files and saved everything.
When I tried to load the page I got a 500 error. I went back and checked the changes I had made and they were fine.
But I could not load the page. I then went back and eliminated part of the path of the address until I came to the Apache Index of the site and there was a missing folder. I can see the missing folder under explorer but not in the index. I also checked the folder properties of the missing folder but was the same as all the other folders. I have several other sites in the main xampp folder and everything is working fine and I can see all of the folders and files.
Does anyone have any ideas.
Barnabas

[Altrea]

check your Apache error.log file.
Most common this happens after some bad changes in the Apache config or an uncorrect .htaccess file

[barnabas]

Thank you for your reply. I will check the log file and the .htaccess file.
barnabas