i m encountering following problem in installation of Bibtex
# JInstaller::install: There is already a folder called 'C:\xampp\htdocs\Joomla\administrator\components\com_afm\' - Please initially check whether:
• the extension is already installed
• the file names in the XML file are spelled correctly
• there are no xml files listed inside the extension.xml file
• all of the files (not including xml files) are correctly listed in the extension.xml file and there are no duplicate entries
• there is an empty folder listed from a previous installation attempt
# Component Install: Could not copy PHP install file.
plz help me out

Are you trying to use Joomla 1.5?  This is not compatible.