2006 MySQL server has gone away Error

A customer contacted me this morning stating she was receiving the following error message:

2006 MySQL server has gone away
in:
[select code, title, symbol_left, symbol_right, decimal_point, thousands_point, decimal_places, value from currencies]

2006 MySQL server has gone away
in:
[select count(*) as total from sessions where sesskey = 'da50df96a2ce72d7bc04f93d898445f9']

I found this post:
http://www.zen-cart.com/forum/showthread.php?t=68047
that has a similar error syntax but no other similarities.

My problem is that I can not re-create this error. If I run the SQL in PHPMyadmin it executes fine. I'm still receiving orders from customers so I know others can still access the store as can I.

Here's the link I sent to her to locate a product:

http://www.pinkchalkfabrics.com/index.php?main_page=index&cPath=39_75_78

She said she received the error when she followed that link. She also tried accessing the store from the browser command line and said she got the error.

I'm not sure what I'm looking for to solve this issue. Any thoughts or directions would be appreciated. I also re-booted my server which did not solve the problem for my customer.

Thank you,
Kathy

Customer reported back that they were finally able to access the store. I have no idea why they received this error. I was never able to re-create so I'm considering this issue closed.