The cvs command generated includes the -d workspace option but this fails with
our module definitions, which look like this (in the CVSROOT/modules):

main -a products/main products/buildsystem products/etc

In this case, you get cvs errors like

cvs checkout: existing repository /usr/cvs/products/main does not match
/usr/cvs/products/buildsystem
...

The solution turns out to be adding the -N option. When combined with -d it
indicates that the directory path should not be shortened to eliminate empty
parent directories, which in this case would be "products." For some reason
this also eliminates the error.

So perhaps you could add that option to the CVS command or otherwise add an
option to specify it, like a checkbox with "checkout modules without empty
parent directories".

Am using cvs version 1.11.17