A new version of monotone is out fixing some bugs in 0.43 and earlier versions. Renaming the current 0.43 ebuild to 0.44 works fine for me on x86-64. Reproducible: Always
+*monotone-0.44 (28 Jun 2009) + + 28 Jun 2009; Patrick Lauer <patrick@gentoo.org> +monotone-0.44.ebuild: + Bump to 0.44, fixes #270827