I am creating a multi-tab spreadsheet programatically but always come
across this error. There doesnt' seem to be any documentation I can
refer to find out what this error means. Can someone help?

Usually this error occurs when I open my newly created spreadsheet. An
error message appears saying that there was a problem with a Table.
Then when I drill down for the error I get this message..pretty
cryptic.

Can anyone help me find out what I'm doing wrong?

XML Spreadsheet Warning in Table
REASON: Cell off grid
ACTION: Ignoring Tag
FILE: <Location of my file
GROUP: Table
TAG: Column
ATTRIB: Width