I have been using version 3.4 without issue. I never updated to 3.5 because I was not aware there was one. When I just tried to update to 3.6 the plugin would not activate and I received these errors:
Warning: require_once(/home/learn75/public_html/site/wp-content/plugins/wp-coda-slider/lib/coda-slider-options.php) [function.require-once]: failed to open stream: No such file or directory in /home/username/public_html/site/wp-content/plugins/wp-coda-slider/wpcodaslider.php on line 16 Fatal error: require_once() [function.require]: Failed opening required '/home/learn75/public_html/site/wp-content/plugins/wp-coda-slider/lib/coda-slider-options.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/username/public_html/site/wp-content/plugins/wp-coda-slider/wpcodaslider.php on line 16
I had a copy of 3.4 so I have downgraded to the last working version 3.4 and it works fine.
I then tried using the 3.5 version found on the developers page and I got this error and the site then fails to load at all:
Fatal error: Cannot redeclare class wpcodaslider in /home/username/public_html/site/wp-content/plugins/wp-coda-slider/lib/deprecated.php on line 70
So I have downgraded to 3.4 again and everything works fine. Please let me know what I can do to help you assist me in resolving this upgrade issue.