cms.root.path error after upgrade to 4.7 (Joomla)
Thanks to eug for finding the problem (see comments). Eug's solution worked for me:  Edit the file administrator/components/com_civicrm/civicrm/templates/CRM/Admin/Form/Setting/Pa‌​th.hlp to replace the first crmResPath with crmResURL 

Update: problem persists in 4.7.3. Have upgraded the bug report priority to Major.

Update: problem persists in 4.7.4.

Update: problem persists in 4.7.5.

Update: fix prepared for 4.7.6. See above bug report link for PR details.

Update: problem fixed in 4.7.6.