I downloaded the Philips LPC2000 PWM Example from http://www.keil.com/download/docs/286.asp, LPC2129_PWM.zip, and opened it up in the uVision5 that's installed on my laptop.
The file opens file (though it says it's uV2), but the build option is grayed out. There's also an error message that says:
*** Error: Project 'PWM' requires 'ARM' Toolchain which is not installed.
I tried to change the tool location in the Manage Project Items, by checking the Use Settings from TOOL.INI, and selecting the path for the Tool Base Folder, but it's no help. Actually whatever I selected disappears after I close the dialog box and reopen the Manage Project Items.
The uVision5.24.1 works fine on my existing project which is also in LPC2000 family (LPC2138).