I've only recently updated to Premiere Pro CC and had a similar issue.
When opening a CS6 file in CC2014, I received this alert:
"The preset used by one or more sequences in this project requires third-party components that could not be located. These sequences will be modified to use a custom setting instead..."
The file would open and I was able to make changes and even save seemingly without any issues. However, when I attempted to open the file again, I was given the alert that you posted here:
"This Project contained a sequence that could not be opened. No sequence preview preset file or codec could be associated with this sequence type."
The problem seemed to originate when a "custom setting" was generated for CC2014 to open the project.
What I did to fix the issue was AS SOON AS I OPENED the older version in Premiere CC, I would immediately go to the Sequence Settings for EVERY sequence in the file and create my own custom settings based on my project. Once that was done, I could begin working on the project and it would save and open without issue. This only needs to be done the first time you open an older version of your project before making any changes or saving the file.
I discovered that the "Custom Setting" that is originally generated when converting the older version to the new, created a funky "Video Preview" size of 16x16 pixels. Once I put all the settings in order, Premiere CC was happy again.
Still haven't figured out a fix for the random crash during operation and the almost guaranteed crash when quitting Premiere from the top menu bar.