Undefined variable

I found what was apprently the issue, and not with WPHTTPS at all.
Jigoshop had writen to my .htaccess file and somewhere along the lines I developed DOS CRLF characters in it, like so:

^M
#Rewrite jigoshop Checkout to https^M
RewriteCond %{HTTPS} off^M
RewriteCond %{REQUEST_URI} /checkout/^M
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [L]^M
^M
#traffic to https://, except /checkout^M
RewriteCond %{HTTPS} on^M
RewriteCond %{REQUEST_URI} !(/checkout/)^M
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [L]^M

It was screwing up a myriad of things ??
I removed all that junk from the htaccess file & all is good.