Dear Vu Nhu Khanh,

I used to have similar problem as yours, and I borrowed the code from Atmel. I used the looped byte write/read (and not page write/read) as you used in your code. I got the sEEPROM reading (or maybe writing? I didn't check) wrong. Then I tried to add some delay (just in case the sEEPROM haven't finished writing/reading process) between processes, and it became normal again. Maybe you need to add some delay between the 1st and 2nd process.

For more information, read Fairchild's datasheet of 24W04 on page 4 - twr section (and note 3). You should find an explanation that after stop bit, the bus interface is disabled for 10-15 ms, so try to add more than 15 ms delay.