For TLDs which have their whois records implemented as a web service, jwhois is configured to use Lynx for fetching data. That dependency is not declared in the RPM, leading to:

[oa@libretto ~]$ whois red.es
[Querying http://www.nic.es/cgi-bin/consulta.whois]
[HTTP: Unable to run web browser: /usr/bin/lynx: No such file or directory]

[oa@libretto ~]$ rpm -q --requires jwhois
/bin/sh  
/bin/sh  
/sbin/install-info  
/sbin/install-info  
config(jwhois) = 4.0-20.fc13
libc.so.6()(64bit)  
libc.so.6(GLIBC_2.2.5)(64bit)  
libc.so.6(GLIBC_2.3)(64bit)  
libc.so.6(GLIBC_2.3.4)(64bit)  
libc.so.6(GLIBC_2.4)(64bit)  
libc.so.6(GLIBC_2.7)(64bit)  
libidn.so.11()(64bit)  
libidn.so.11(LIBIDN_1.0)(64bit)  
rpmlib(CompressedFileNames) <= 3.0.4-1
rpmlib(FileDigests) <= 4.6.0-1
rpmlib(PayloadFilesHavePrefix) <= 4.0-1
rtld(GNU_HASH)  
rpmlib(PayloadIsXz) <= 5.2-1

/etc/jwhois.conf has a commented-out example of how to use w3m instead of lynx, but that isn't a dependency either. For some reason, w3m is installed on my computer, though lynx isn't.