Ошибка при сборке SpamAssassin

Подскажите, что ему не хватает? А лучше, хорошую документацию по его установке и настройке. /usr/bin/perl version.h.pl version.h.pl: creating version.h spamc/configure.pl: version.h.pl: Failed to get the version from Mail::SpamAssassin. Please use the --with-version= switch to specify it manually. The error was: version.h.pl: version.h.pl: version.h.pl: version.h.pl: version.h.pl: version.h.pl: version.h.pl: Can't locate Digest/SHA1.pm in @INC (@INC contains: ../lib /usr/lib/perl5/5.8.4/i486-linux /usr/lib/perl5/5.8.4 /usr/lib/perl5/site_perl/5.8.4/i486-linux /usr/lib/perl5/site_perl/5.8.4 /usr/lib/perl5/site_perl .) at ../lib/Mail/SpamAssassin/EvalTests.pm line 33. BEGIN failed--compilation aborted at ../lib/Mail/SpamAssassin/EvalTests.pm line 33. Compilation failed in require at ../lib/Mail/SpamAssassin/PerMsgStatus.pm line 56. BEGIN failed--compilation aborted at ../lib/Mail/SpamAssassin/PerMsgStatus.pm line 56. Compilation failed in require at ../lib/Mail/SpamAssassin.pm line 74. BEGIN failed--compilation aborted at ../lib/Mail/SpamAssassin.pm line 74. Compilation failed in require at version.h.pl line 27. make: *** [spamc/Makefile] Ошибка 2