Try run AFX in Administrator mode, make sure your composition's name doesn't include any special characters and don't forget to add exceptions to your firewall.
I am also getting this problem, I do get a pop up box saying that After Effects appears to have crashed, which it has not. Press yes and then get this error I am on AFX 17.5.1 (Build 47) - I can turn on debugging and send a report if required.
Hello. Firstly, that pop up is not saying that AE crashed, only that it may APPEAR frozen. Secondly, make sure you have a comp selected when you press squirt and that there are no special characters in the name of the comp or the path of the project file.
I am also getting this problem, I do get a pop up box saying that After Effects appears to have crashed, which it has not. Press yes and then get this error 
I am on AFX 17.5.1 (Build 47) - I can turn on debugging and send a report if required. 
