Knowledge Base FAQ Item #3650030

Q3650030: I'm using XAMPP to run your ActiveX component. I get the error: "Uncaught com_exception: Failed to create COM object 'AxSerial.ComPort': Invalid syntax in C:\Xampp\htdocs\serialport\index.php". What's wrong?

First of all, COM is enabled on Xampp, so there's no need to modify PHP.INI. The problem is that the ActiveXperts COM component is not registered. Best is to register both 32-bit and 64-bit DLL's, so you're not dependent on the type of web-application or Xampp version (32/64 bit). The 32-bit and 64-bit ActiveX controls can both be registered at the same time without a conflict.

So, make sure you register both 32-bit and 64-bit DLL's from the command line in Admin mode:
REGSVR32 AxSerial32.dll
REGSVR32 AxSerial64.dll