addAnnotMarkup returns false

Hi, I've tried calling addAnnotMarkup but it always returns false without any clear idea why.

this is my usage:

returnValue = [m_page addAnnotMarkup:index1 :index2 :color];

"
index1 = 0
index2 = 29
color = -256 (yellow)
"

I've called

[m_view vRenderSync:pageNo];
[self refresh];

afterwards but no highlights show up.

I don't see any methods on the API like getLastErrorMessage() to get an idea of the internal state or why I was using the API incorrectly. If they don't exist please can you add them in future releases so that someone without a copy of the C/C++ source code can debug their applications.

* Please note it's a password protected PDF

Three reasons could rise annotation creation failure:
- you aren't activating a Professional or Premium license
- you're working on a file without writing permissions
- you're working on a file with limited password (not owner)

May you check the above points?