I was getting mad about this, but for any reason if you only make only 1 Row, contractUpdate() is not working.
Sure is my fault, but why i can not read about this in the documentation?

#include<contract.c>

void main(){

int Today = (int)wdate(0);

int j;
int k;
k=2;
//k=1; // uncomment this line and no contract will be updated
CONTRACT* C;
dataNew(1,0,9);

for(j = 0; j < k; j++)
{
C = dataAppendRow(1,9);
C->time = wdate(0);
C->Expiry = Today+1;
C->fStrike = 100;
C->fUnl = 100.21;
C->Type = CALL;
C->fAsk = 19.99;
C->fBid = 17.16;
}

contractUpdate(Asset,1,CALL|PUT);
contractPrintChain (); // *.csv in Data folder will be empty if k<2

}