VLOOKUP - value not found HELP

Hello,

I'm attaching example excel file.

I need to compare data from first sheet with data from second sheet. Please take a loot at green column in first sheet.
For some reason, VLOOKUP is providing me incorrect DATA - is there any way to tell VLOOKUP to insert "0" if it can't find the exact value in second sheet?

Thanks a lot for any help.