But officials used an old database containing out-of-date information on contractors in the county.
One contractor said: 'It seems the Revenue has fallen at the very first hurdle so what hope is there for the future?
'We received two letters, both of which were wrong. One had our correct tax reference but was sent to my home address and didn't contain our trading name.
'The other was sent to our office but was addressed to a company we closed three years ago.
'I spoke to the tax office and they've had hundreds of calls complaining about mistakes - I even heard they'd sent letters to people who are now dead.'
The mailshot was the Revenue's first warning to contractors about what action they should take in the run-up to next April's changes.
A Revenue insider confirmed that old records were used for the mailing and described the mistake as 'very regrettable'.
A spokesman said: 'The database used wasn't the most recent.'
Industry leaders fear computer and software systems to implement the system are not ready and will fail, resulting in chaos.
Another Gloucester contractor said: 'We had the wrong details on our letters. We had the wrong trading name. What if someone rings up next April to check if we should be paid gross of tax and the
Revenue has the wrong records? We'll be hit with an emergency tax rate of 30 per cent through no fault of our own.
'This is the first CIS campaign the Revenue has launched and it has gone belly-up because of an IT failure.'