Quote from: belenus PHP Error in /vhosts/blah/htdocs/webmail/program/include/rcmail_template.inc (252): Error loading template for 'login'
I will point out that I had this exact error message as well. I see you edited out sensitive path information, but let me ask if you have a space in the local path of your website directory structure? For example, is your website located at "c:\web sites\example.com" ?
Mine was, and when I coped the website to a directory without a space, i.e. "c:\website\example.com" it seems roundcube had no problems. Apparently spaces in directory paths screws up the relative paths and causes this error. Hope this helps.