Hi jzhou,
First, thank you for your help!
Unfortunately add a glFlush(); command to the code did not help the situation.
Win7 version still suffers GL ERROR: 1, out of memory, and no texture, even if the code is correct on Ubuntu.
( The GPU has 2 Gbyte allocated RAM in both op. system, so this error msg. is quite a surprise..)
Regarding ATI_meminfo:You are absolutely right!
Based on your hint, I have checked the system with OpenGL extensions viewer tool by realtech, and Kaveri does not support this extension according the tool. ( Even If the reported numbers look really valid at first sight, and that makes me fool. )