cryptkeeper can't complete

[Joep]

An encrypted file that was created with cryptkeeper in Ubuntu 10.04 can no be decrypted in 12.04.1.
Symptoms:
Pushing the cryptkeeper icon gives the expected cryptkeeper window with as upper line the encrypted folder in this case:
/home/../../../Datavault (the encrypted directory is /home/../../../.Datavault
When I ciick on the upper line, the expected window with as header cryptkeeper pops up with the question:
"Enter your password".
When I enter either the correct or an incorrect password then after 2 - 3 seconds I get an error window with the following text:
"terminate called after throwing an instance of 'std::runtime_error". and a 'cancel' button.
When I push the cancel-button the cryptkeeper header window pops up again requesting the password. This goes on until I push the cancel button on the cryptkeeper window.
This behaviour prevents the decryption of the encrypted folder.
It is a bug at least in 12.04.1 as I have tested cryptkeeper in ubuntu 11.10 running as guest under VMware using the same encrypted directory and there the file was decrypted without any problem.
As I don't think that cryptkeeper has changed between 10.04 and 12.04 I can only assume that one of the upgraded libraries is the cause.