frm-40039 or frm-10102 can't attach PL/SQL library while opening form

Problem: FRM-10102: Cannot attach PL/SQL library APPCORE. 

This library attachment will be lost if the module is saved Solution. 

Need to add FORMS_PATH  in registry of windows.

Press Win R to open windows Run and put regedit to edit the windows registry.

and search ofr FORMS_PATH and custom Forms and plls path in this variable.

OR

FORMS_path variable in regedit.

   FOTMS_PATH=c:\DevSuiteHome_1\cgenf61\admin;