LORD Killanin and his wife Sheila were the unofficial guests of honour at the launch of the programme for this year's Dublin Theatre Festival and with good reason. Lord Killanin was one of the founding members of the annual event which has been bringing all kinds of new theatrical experiences to Dublin audiences since 1957. During the October festival, some of the most interesting shows are in the more unexpected venues. The Royal Shakspeare Company will be performing The Comedy Of Errors at DCU and a French Company will be taking over the basketball arena in Tallaght to stage Les Dariaides which has a cast of 110 and needs a stage of 8,000 square feet and is by far the biggest show ever staged in Ireland. The indefatigable Eithne Healy is this year's festival chairwoman and after the launch she and festival director Tony O'Dalaigh - who are just back from Stratford - are off on a two-day trip to Edinburgh to take a look at nine shows - making most culture vultures look like lowbrow slackers.