The documentation for "AN 690: PCI Express Avalon-MM DMA Reference Design" is at:
I am directed to:
And click on 'G3x8_avmm_dma.qar' to download, I am directed to:
How do I download the reference design?
The issue is fixed. Please try to download the design again.
I tried from my end and it is working.
After you get the QAR file, you suppose can compile it with quartus.
And if quartus compilation give you complaint about license, then you can visit this page and learn how to obtain the license.