This isn't really a problem with FS2_Open as you've stated that you got it in retail. So maybe we need to solve the underlying problem rather than trying to figure how to get the bandaid to stick to the enormous bleeding wound then
Your problem appears to be that you have no NTF Iceni in the version of the ships.tbl that your copy of FS2 is using. That leads me to believe that you've installed a mod (my guess would be Derelict) that has removed it. So what you need to do is go back to a proper FS2 install with no mods installed.
The simplest way to do that is simply to reinstall (back up your Freespace2\Data\Players folder first) but if you're reluctant to do that for some reason go into your Freespace2\data\tables directory and check for a file called ships.tbl. If it exists rename it file to something like disabled-ships.tbl
If that doesn't solve your problem or you find no file by that name (It may be hiding else where in your FreeSpace 2 folder) your problem is most likely a rogue .vp file.
The Official .vp files have the following names
* root_fs2.vp
* sparky_fs2.vp
* sparky_hi_fs2.vp
* stu_fs2.vp
* tango1_fs2.vp
* tango2_fs2.vp
* tango3_fs2.vp
* smarty_fs2.vp
* warble_fs2.vp
If you have a vp file that with mv_ then move it to a folder called MediaVPs. (You can drag them out later but for the moment lets rule them out as the source of the problem). Any other files should be deleted, renamed to .extentionDisabled or simply put in a folder like Freespace2\JunkI'llDealWithLater.