Since the contest is over, it is time for me to reveal the way I figured out to solve the code.
So the code is '02201010121021210121111011020201012110221021210202010121022210202111111102101012110101021001012021121020210121110221021201012101211100210201010121101010210010120220010121102011020211021012010101202112101211111101012021120101202021010120121201210012110121201211012120121201211' which is 275 numbers long. As this had to be 'converted' into text, it made sence these were groups of numbers. The first number you can devide 275 by is 5.
So lets take a look at the first 5 numbers: 02201. The first thing I thought of was that this was a base-3 number. This means that the decimal number would be: 1x30 + 0x31 + 2x32 + 2x33 + 0x34 = 73.
This number falls right in the range of the ASCII table. ASCII is the most used way to store characters in computers as a number. In this case 73 = I. Doing this for the rest of the numbers created the solution 'I have the keys of Death and of Hades. Day D = 20121221'
P.S. Thanks MADFINGER Games for this competition, looking forward to the t-shirt