I was trying to install Office Web Apps on my SharePoint server farm and came across this error when I launched the installer: "Windows server features or role services required by this product are not enabled"
I checked all the prerequisites listed under the Hardware and Software Requirements (SharePoint Server 2010) and they are all there.
After a bit of head scratching, I decided to launch Server Manager and see what roles and features were installed. I clicked on Add Feature and it complained that another user was still configuring a role. It turned out that when I was enabling the Desktop Experience Feature using a different account, however that required a reboot and was waiting for that account to login again in order to continue the installation of Ink and Handwriting Services. Once I logged in, that feature was successfully enabled.
Then the prerequisite check succeeded.