If you look at the package steps, you can see that the package tries to access the files below. {PackageShare} refers to the package share(s) configured in the web console under Deployment\Security Options. By default, your package share is the Program Files (x86)\Lansweeper\PackageShare folder on your Lansweeper server. In other words, you need to add IE11-Windows6.1-x86-en-us.exe and IE11-Windows6.1-x64-en-us.exe to the Program Files (x86)\Lansweeper\PackageShare\Installers\IE11 folder on your Lansweeper server. If the PackageShare subfolders don't exist, manually create them. The executables themselves can be downloaded
here. I'm not sure from your description which folder you added the files to, but it's likely not the correct one.
I would recommend reading up on the deployment module prior to running any deployments. More information on creating and running deployment packages can be found in
this section of our knowledge base.
{PackageShare}\Installers\IE11\IE11-Windows6.1-x86-en-us.exe
{PackageShare}\Installers\IE11\IE11-Windows6.1-x64-en-us.exe