How to rectify modelsim error "missing ALT2GXB.v"?

[Altera_Forum]

I was trying to simulate PCI Express reference design as per instructions given in "IP compiler for PCI Express" document. Reference design file I downloaded from altera website and copied in the system. When runtb.do file is runned an error message missing "ALT2GXB.v" is shown in the screen.  

 I tried to download this file. But I am not getting any source. Help please.

[Altera_Forum]

Probably some screenshot or Modelsim error message will be helpful. Also, you might want to share the link of the reference design for clarity.

[Altera_Forum]

Thank You @bfkstimchan for your response. Problem solved. Will post solution that I found as answer to my question.

[Altera_Forum]

ALT2GXB.v file was available in quartus library. I copied that file pasted in respective folder. Now modelsim is not throughing any error.

[Altera_Forum]

Glad to hear that you have found the workaround. It seems like this ALT2GXB.v file is missing from the reference design that you have downloaded?

[Altera_Forum]

By the way, mind sharing the reference design link which seems to have missing file?