FND SESSION issue with call fnd_flex_ext.get_ccid

I am using following code to create code combination in GL flexfield tables and found that code always fails with validation error saying Value 02 for the flex-field segment Company does not exist in the value set COMPANY SEGMENT.''

When I use similar code as procedure/function and call using concurrent program, it works fine.  I am not sure what's going wrong with code below. Need help to resolve and provide pointers.

Thanks for help in advance.

DECLARE

  p_segment1 GL_CODE_COMBINATIONS.SEGMENT1%TYPE;

  p_segment2 GL_CODE_COMBINATIONS.SEGMENT2%TYPE;

  p_segment3 GL_CODE_COMBINATIONS.SEGMENT3%TYPE;

  p_segment4 GL_CODE_COMBINATIONS.SEGMENT4%TYPE;