I have ZC 1.5 The mapping works great with the .htaccess file in place however my paypal express will not connect to paypal after adding this file. If I remove the .htaccess then the mapped pages give a 404 not found. I suspect the rule needs revising, but I have no clue what to change.
Here is the rule being used:

## BEGIN CEON URI MAPPING REWRITE RULE

RewriteEngine On

# Don't rewrite "cpanel" directory
RewriteCond %{REQUEST_URI} !^/cpanel/ [NC]
# Don't rewrite any URIs ending with a file extension (ending with .[xxxxx])
RewriteCond %{REQUEST_URI} !\.[a-zA-Z]{2,5}$ [OR]
RewriteCond %{REQUEST_URI} \.(html|htm|php)$ [NC]
# Don't rewrite any URIs for some, popular specific file format extensions,
# which are not covered by main file extension condition above
RewriteCond %{REQUEST_URI} !\.(mp3|mp4|h264)$ [NC]
# Don't rewrite any URIs for some specific file format extensions,
# which are not covered by main file extension condition above
# Uncomment the following line to apply this condition! (Remove the # at the start of the next line)
#RewriteCond %{REQUEST_URI} !\.(3gp|3g2|h261|h263|mj2|mjp2|mp4v|mpg4|m1v|m2v|m4u|f4v|m4v|3dml)$ [NC]
# Don't rewrite admin directory
RewriteCond %{REQUEST_URI} !^/ad_ff_min [NC]
# Don't rewrite editors directory
RewriteCond %{REQUEST_URI} !^/editors/ [NC]
# Don't rewrite temp directory
RewriteCond %{REQUEST_URI} !^/temp/ [NC]
# Don't rewrite old_editors directory
RewriteCond %{REQUEST_URI} !^/old_editors/ [NC]
# Don't rewrite ffdocs directory
RewriteCond %{REQUEST_URI} !^/ffdocs/ [NC]
# Handle all other URIs using Zen Cart (its index.php)
RewriteRule .* index.php [QSA,L]

## END CEON URI MAPPING REWRITE RULE