USGS optional DLG and SDTS formats

[Brook Milligan]

I am trying to read in the USGS DLG (1:100K), but am having trouble.
What is the trick?

I downloaded the optional format files, uncompressed them into the
appropriate dlg directory, and ran v.in.dlg.  The program begins to
read the file but reports the following:

ERROR: Number of sides in the polygon defining the coverage
         of the map less than 4.
25400000000D+01     4     0     4     1                -0.106007030000000D+09   0.3202203
Another words the Dlg header is incorrect.
Dlg header line 4, data element 8.

Is there another procedure?  Do the files need translating somehow
first?  Can I use the SDTS formats instead?

Thanks for your help.

Cheers,
Brook