Installation Issue

I have successfully installed PP onto my site but when I go to www.asentiaanimalhealing.co.uk/projectpier/ I see the following:

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Warning: include_once(projectpier/environment/environment.php) [function.include-once]: failed to open stream: No such file or directory in /home/asentiaa/public_html/projectpier/init.php on line 83

Warning: include_once() [function.include]: Failed opening 'projectpier/environment/environment.php' for inclusion (include_path='/home/asentiaa/public_html/projectpier:/home/asentiaa/public_html/projectpier/application') in /home/asentiaa/public_html/projectpier/init.php on line 83

Fatal error: Class 'AutoLoader' not found in /home/asentiaa/public_html/projectpier/application/functions.php on line 18
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Can anybody help me please?