Error 049: Too many trades
This error happens sometimes when there is both an adviseLong and an adviseShort, and TradesPerBar has not been bumped above the default of 1. Other times, the error does not happen. And I haven't had success isolating that. It's a black box.

Anyway, I think this message could be made more informative. First, the message should be, "Too many trades of the same asset in the same bar", since that's the only reason for the message listed here http://manual.zorro-trader.com/errors.htm
Second, the number listed in parenthesis is a distraction. It's a number without a label. I think that's the total number of trades? Or the process id? I don't know what that is. Anyway, that should be a (2), in other words, TradesPerBar+1.
So something like
"Error 049: Too many trades of the same asset in the same bar (2 trades of EUR/USD in Bar 1)!"
Instead of
"Error 049: Too many trades (4303)!"
would have saved me many hours of hair-pulling. Thanks.

Good suggestion - we'll change that in "too many trades per bar". But normally all possible reasons are described for any error number in the manual, so for the sake of your hair, look there first.

Great. One more thing.
In the SED UI, TradesPerBar is not highlighted. And, nothing shows up in the Command Help window when the cursor lands on TradesPerBar. That made me think it was deprecated.

What does the 4303 mean anyway?

I just got a Error 049: Too many trades (409200)! on a Strategy that enters 686 trades per bar (for Training purposes). But TradesPerBar is set to > 686.

What limit am I actually hitting, here?

Most likely a hard limit - as to my knowledge there is a 12 MB limit to the trade list, no matter how many trades you open per bar. This is probably hit by your 686 trades per bar.

There is no particular reason of that 12 MB limit that I know, so I'll check if it can be removed alltogether.