OpenAL - alBufferData and AL_INVALID_VALUE

I have a problem. When I buffer data, I get error 40963 back, which means AL_INVALID_VALUE. The programmer's guide (http://connect.creativelabs.com/openal/Documentation/OpenAL_Programmers_Guide.pdf) says that the data is zero, the buffer used or the size parameter is invalid.

I know that the data is not null, and the buffer is not used. But what does “size parameter invalid” mean? For example, each packet that I want to download is 20 ms and the data size is 320. My rate is 8000 kHz.

thank