When I run download nothing really happens (Zorro does not even try to connect to the broker, which it used to do). However, I cannot remember having changed anything important aside from the asset list.
Here is the script:

// Download Assets.dta and update price history of a certain asset (or all)

// comment this in and click [Trade] for updating Assets.dta
#define LOAD_ALL

function run()
{
// set date and click [Test] for downloading price history (not with MT4)
StartDate = 2009;
EndDate = 2013;
string name = "EUR/CHF";
#ifdef LOAD_ALL
while(name = loop("AUD/USD","AUD/JPY","EUR/CAD","EUR/JPY","EUR/GBP","EUR/USD","EUR/CHF","GBP/USD","GER30","NAS100",
"SPX500","UK100","UKOil","US30","USD/CAD","USD/CHF","USD/JPY",
"USOil","XAG/USD","XAU/USD","NZD/USD"))
#endif
{
if(is(TESTMODE)) loadHistory(name,1);
if(is(TRADEMODE)) asset(name);
}
}