Xampp autoload.php Error

[Squirtre]

i keep getting this error.
Warning: require(C:\xampp\htdocs\bootstrap/../vendor.autoload.php): failed to open stream: No such file or directory in C:\xampp\htdocs\bootstrap\autoload.php on line 17

Fatal error: require(): Failed opening required 'C:\xampp\htdocs\bootstrap/../vendor.autoload.php' (include_path='.;C:\xampp\php\PEAR') in C:\xampp\htdocs\bootstrap\autoload.php on line 17

[Squirtre]

and im trying to run technicsolder...

[Altrea]

technicsolder is a third party application
=> [INFO] How to not fail getting help here (Section: Scope of support)

Evaluate if your topic is in scope of support of our board. We don't want to provide...
[...]

• ...support for third party applications like WordPress, Joomla!, phpBB, Skype, etc.
  There are several hundred of thounsand of these applications out there, all of them with their own requirements, characteristics and issues.
  The developers of these applications are knowing their own software best and commonly provide their own support channels where you can get proper support relating to this specific product.

[...]

But a wild guess: Technicsolder is based on composer. Did you run the composer install command as listed in the installation instructions https://github.com/TechnicPack/TechnicSolder/wiki/Getting-Started?