Gerber dies for me too. It looks like one or both of the custom parts are incorrect, I’ll have a look and see if I can correct them. DRC is reporting overlaps which likely means incorrectly configured parts:
edit1:
To my surprise it isn’t the user supplied parts (although both are wrong) but the Q4 sot23 transistor from core parts (I don’t yet know why). I deleted all traces and most of the parts (leaving the holes and vias) verified it would export as a gerber, then added the parts back in one by one by undoing the deletes one at a time then doing the gerber export until it broke at Q4. This sketch (with Q4) breaks in gerber export:
with Q4 removed it exports successfully. I’ll have a look at the part and see if I can see why it is breaking.
the sketch the above two images were created from so you can try it for yourself. This sketch should die in gerber export, deleting Q4 fixes that.
relay-led-motor-V2_2_gnd_2switch_V2.fzz (5.6 KB)
edit2: A workaround (this appears to be a Fritzing bug which I will report!) If you change the rotation of Q4 from 180 to 179 gerber export then works:
That still leaves the part errors though. For the esp32, replacing the current par with this one should fix things up:
Here is a fixed copy of the other custom part. The current one lacks a copper1 layer in pcb among other faults. The moduleId is the same so you will need to delete the current part (and shutdown and restart fritzing to really delete it) before you can load this one.
DC 5V to 3.3V DC-DC Step-Down Power Supply Buck Module AMS1117 LDO 800MA-fixed.fzpz (6.6 KB)
Some of your vias are overlapping parts. This will work fine usually, but will cause DRC to complain.
Peter