Using Custom column causes error with loss of predecessors

What steps will reproduce the problem?
1.Create a task1
2.In Task properties, Custom Columns, Manage Columns, add a column (e.g. Cost, 
integer)
3.Create a new task2 and make task1 a predecessor
4. Add values to the 'cost' column
5. Save the project. Exit

What is the expected output? What do you see instead?

6. Try to open the saved project. Ganttproject does not start.
7 Start GantProject from the taskbar and open the saved project
7.1 Get message 'something went wrong, null'
8. The project will open, But: a) value in cost is reset to 0, and b) 
dependency is no longer visible in the Gantt Chart.

What version of the product are you using? On what operating system?

Using 2.5 Beta Build 888 on Windows7
Please provide any additional information below.

Original issue reported on code.google.com by ian.hay....@gmail.com on 2 Feb 2012 at 5:08

Merged into: #404

Attachments:

ganttproject.log.5

bardsoftware / ganttproject

Using Custom column causes error with loss of predecessors #417