That is a strange issue..
Can you increase the sampling size to anything higher than the "Count"?
Your count is 343809 so try to use a sampling size of 345000, for example.
I think by default your sampling is set to ~10,000.
Look back at your first post, in the first screenshot.
The sampling button is in the window where you modify the 'class ranges'.
I think you press the "Classify" button inside the "Reclassify" tool.
Jamal,
Please follow the steps in the knowledge base article to resolve this issue.
HowTo: Compute the histogram with all the unique values, when using the classified renderer
Regards,
Eric