Ok, this is now a bit complicated, because I speak no Polish. (Except for the few words you taught me.)
Apparently, Polish has 3 plural forms:
1. There's only one element
2. There are 2-4, but also 22-24; 32-34;... elements
3. There are 5-21, but also 25-31;35-41;... elements
Is this correct? If yes, please revise all strings I marked fuzzy. Those with msgstr[0] are singular - above case 1); those with msgstr[1] are 2,3,4,12,13,14,... and those with 5,6,...,20,21,25,26,...,30,31,... are msgstr[2].
Anyway, I'll commit the translation as it is now (singular and one plural form for 2,3,4,5,...,20,21,22,... [well: all n > 1]), thanks a lot for your work!