hi there, ive been trying to change my default currency to canadian dollars so i went to localization, currencies and made canadian my default currency but when i tried to update it it gave me this message:

2006 MySQL server has gone away
in:
[update zen_currencies set value = '0.97227795', last_updated = now() where currencies_id = '1']
If you were entering information, press the BACK button in your browser and re-check the information you had entered to be sure you left no blank fields.

2006 MySQL server has gone away
in:
[select count(*) as total from zen_sessions where sesskey = '5e55fff159a8f4b9d2ba87acd10db817']
If you were entering information, press the BACK button in your browser and re-check the information you had entered to be sure you left no blank fields.

please help me, what does this mean?