oracle forms designer has stopped working

Dear Oracle forms experts,

Currently, when i open a form with oracle forms builder, it come out the attached screenshot error, and then exit. when i connect the form bilder to database, then open the form again, it works fine. could you pls help me?

my forms builder product comprise with below part:

orms [32 bit] version 10.1.2.0.2 (standard version)

Oracle Toolkit version 10.1.2.0.2 (standard version)

PL/SQL version 10.1.0.4.2 (standard version)

Oracle Procedure Builder V10.1.2.0.2 - Production

PL/SQL Editor (c) WinMain Software (www.winmain.com), v1.0 (Production)

Oracle Query Builder 10.1.2.0.2 - Production

Oracle Virtual Graphics System version 10.1.2.0.2 (standard version)

Oracle Tools GUI Utilities version 10.1.2.0.2 (standard version)