When checking any UNIMARC implications of bug 5582 encountered the opaque variable name fieldnumber. It does not refer to a field but the ISBD block (an organizing principle of UNIMARC) Change variable name to reflect what it is/does. Clarity is a virtue if you have to maintain the code.
Created attachment 2953 [details] [review] Proposed Patch
Pushed, please test
This bug is mentioned in: Bug 5583 Rename fieldnumber to blocknumber http://lists.koha-community.org/pipermail/koha-patches/2011-January/013531.html