Coupon Admin --> Email function killing system?

This may be related to my other post, but it could also be a good stand alone issue so I am posting it here.

When I go to Coupon Admin, select a coupon, and then click the Email button, it spawns a MySqlD process that sucks up my CPU.

When I Trace this MySqlD processes that is sucking up a lot of CPU, I see something like this:

Process 17815 attached - interrupt to quit
pread(34, "\1\1\361\374\357\337\277\377\361\17\0 \341\220\17\0\0\t"..., 20, 1759996) = 20
pread(34, "\0\nPete Geist\16PG Productions\0221800"..., 480, 1760016) = 480
pread(34, "\3\1\276\2\374\357\337\277\377\361\17\0 \341\221\17\0\0"..., 20, 1760496) = 20
pread(34, "\0\0\fDinesh Senan\3DSA\n2 Kew Walk\tS"..., 430, 1760516) = 430
pread(34, "\3\1\217\1\374\357\337\277\377\361\17\0 \341\222\17\0\0"..., 20, 1760948) = 20
pread(34, "\0\0\vJohn Harris\0\0211885 Rockledge R"..., 383, 1760968) = 383
pread(34, "\3\1\300\0\374\357\337\277\377\361\17\0 \341\223\17\0\0"..., 20, 1761352) = 20
pread(34, "\0\0\vJohn Geerts\vArcane Soft\21Rue d"..., 432, 1761372) = 432
pread(34, "\3\1\276\2\374\357\337\277\377\361\17\0 \341\224\17\0\000"..., 20, 1761804) = 20
pread(34, "\0\0\16Anibal Aguirre\4MCAS\02611343 S. "..., 430, 1761824) = 430
...etc....

I just killed that process through WHM and it brought the system back to normal. Then when I go to Coupon Admin --> Email, it hangs again with the above process being started. What on earth is causing that? In the past, when I click on EMAIL within the Coupon Admin, it would take me to a form where I could email the coupon to a recipient. Now when I click on it, it hangs the entire system and the above process begins. Why is that?

NOTE: After I manually killed the process, the webpage returned with the following error:

2013 Lost connection to MySQL server during query
in:
[SELECT DISTINCT c.customers_email_address as customers_email_address, c.customers_lastname as customers_lastname, c.customers_firstname as customers_firstname FROM zen_customers c LEFT JOIN zen_orders o ON c.customers_id=o.customers_id WHERE o.date_purchased IS NULL ]