Setting File Length

Hello. I have this code:

Data4* data;

data = new Data4(_db, fullPath.c_str());

if (data->seek(t.GetId()) == r4success)
{
    data->deleteRec();
    data->pack();
}
data->close();

delete data;

When I get to the data->pack thing, it throws me the following error:

Error #: -40
Error #: 90606
Setting file length file4lenSet \storage card\db\employee.dbf

Why's that? It's a simple pack, don't understand why such error is
displayed. And furthermore, there's no do***entation about that error
in the manuals and reference book. Does anyone have a clue?

I'm working with CB 6.5 for Visual C++ 2005, for Windows Mobile 5.

Thanks in advance.