Tax implications while travelling

I am planning to go traveling for a year in June 2005, will this affect my PRSI (stamps) or is there a provision to allow a gap period in payment. Also, will I be able to reclaim any unused tax credits, if yes how much?

You need 39 weeks to be paid in a year to get your prsi entitlements if you are short then 2 years later you will lose your unemployment ,dental etc benefits for that year