problem to update virtue 2.14

[enzoibanez]

hi..i had a joomla site in local..i use xammp 1.7.3 whit MySQL: 5.1.41
the update give me this error

JDatabaseMySQL::query: 1118 - Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. You have to change some columns to TEXT or BLOBs SQL=ALTER TABLE `pz1mh_virtuemart_products_it_it` ADD metadesc varchar(400) NOT NULL DEFAULT '' FIRST

i'm newbye and what i will do to update correcly