vlookup wont work ??

[vxg]

hi everyone, just hoping someone would help me with this problem, basically my vlookup formula that I entered wont work (please see the example file), essentially I have numbers like the one in A3 which I got from concatenating two variables I obtained from one database.

In another workbook I would have rows (approx 200000 rows) of variables like the one in row 1. This I obtained from another database.

I then need to extract the data in second workbook to first workbook. I used vlookup which work for most identifiers but not all. any suggestions whats wrong and how to fix it ??

thank you.