Here is the list of supported WICs from the Cisco Website
The Cisco 1720 router supports any combination of one or two of the following WAN interface cards, which are shared with the Cisco
1600, 2600, and 3600 routers:- WIC-1T: One port high speed serial (sync/async)
- WIC-2T: Two port high speed serial (sync/async)
- WIC-2A/S: Two port low speed serial (sync/async) (up to 128 kbps)
- WIC-1B-S/T: One port ISDN BRI S/T
- WIC-1B-U: One port ISDN BRI U
- WIC-1DSU-56K4: One port integrated 56/64 kbps 4-wire DSU/CSU
- WIC-1DSU-T1: One port integrated T1 / Fractional T1 DSU/CSU
So the card you're trying to use is apparently not supported.
Dennis
snipped-for-privacy@m> I have a 1720 with 32/8mb running IOS c1700-ny-mz.122-31.bin