Getting error ORA-06502: Character string buffer too small when using PL / SQL.

I'm having this error when using datagrip and executing a PL / SQL file on my pc. The code I have runs on SQL Developer without a problem and also on the console. However, when I try to run it using DataGrip it gives me the following error: 

[2017-02-11 17:57:58] [65000][6502] ORA-06502: PL/SQL: numeric or value error: character string buffer too small
[2017-02-11 17:57:58] ORA-06512: at line 3

I've already search for this errors and the main cause is assigning wrong values to certain variables or assigning a larger value than the one declared. However, I have meticulously re-read my code and I haven't made any mistakes of that sort. This is the code I'm having problems with: http://pastebin.com/QX12BK6s.

It should normally also prompt user input, and it doesn't. Please, any help / advice would be appreciated a lot. 

Thanks in advance!