By default MySQL has a data limit of 4.2GB for a MyISAM table.
To increase the size use the following SQL statment:
alter table `table_name` max_rows = 200000000000 avg_row_length = 50;
*Notice the orange text indicating where you would enter the table of which the increase is required for.
Now simply type the following SQL statment:
show table status;
and you will see the Max_data_length has been increased.
There is still a limit on MySQL for 32-bit processors of 4.2 billion rows. To increase the maximum rows allowed you would require a 64-bit processor.