a strange problem about original file upload

hello,

write a function to upload original of document master,

test user: test_user

importing parameter:dokar,doknr,doktl,dokvr

processing:

1. delete document master's having original file,and commit work with function BAPI_DOCUMENT_CHANGE2;

2.upload new original file with function BAPI_DOCUMENT_CHANGE2 too.

now problem is :

when I tested the function in execute (F8), return error is:

document is freezed by test_user

and result is original wasn't uploaded.

but,when I tested it in debug(Ctrl +F7), result is right,no any problem.

this situation is caused what reason?

please help me.