[plt-scheme] csv.plt - expand: unbound variable in module in: set-cdr!

Hi,
Is this something wrong with my drscheme configuration (which i always 
find confusing) or incompatibilities with v4

Settings:
Language: Pretty Big (includes MrEd and Advanced Student); memory limit: 
128 megabytes.

Used:
(require (planet "csv.ss" ("neil" "csv.plt" 1 1)))

Thanks