#009317: fatal error at importing package

Hi,

I've created a new class with a datetime field.

Then I've created some objects with the new class and exported them to a package.

At importing the package, I am getting a fatal error:
Fatal error: Call to a member function on a non-object in \kernel\classes\datatypes\ezdatetime\ezdatetimetype.php on line 472
Fatal error: eZ publish did not finish its request

php 4.4.2, mysql 5, ez 3.8.4

Import the package.

The fatal error occurs after creating the class.