You didn't say how you were declaring this, or if you intended it to be a constant or not. However, the Stack error would indicate you declared it as a local function variable (not constant). To fix that problem add the 'overlay' keyword to your declaration:
char [50][10] are 500 bytes, and in a PIC18 all ram banks are 256 bytes... so if you want that vector in ram you must "fuse" to banks (with the linker script and the #pragma data) there are lots of examples ot doing that...