Application crashes when making a field expression a model parameter and then accessing it from a tool

Description

** This issue is addressed in ArcGIS 9.0 Service Pack 2 (SP2) **

Fatal error will occur when making the Field expression a model parameter and accessing it from a tool.

For example, Add Calculate Field to Model Builder. Make the field expression a variable and set as a model parameter. Save the model and close. Double-click the model and try to bring up the field calculator. The application fatals.

Cause

Workaround