To simplify this, I think you are saying that in v2.4, you see that a formula like this =if(A1-B1<>0;1;C1) returns an error 529 when C1 contains "" and A1 and B1 are empty
I made a simplied test case in OOo 2.4 (the lenny version) The formula behaves the same in 2.4 and 3.0. My 3.0 is the experiemental version. In both cases, the formula evaluates to "" I think you are trying to report this:
bug504604_1.ods
Description: application/vnd.oasis.opendocument.spreadsheet
