ATTENTIONATTENTION: This port requires a kernel built with the directive: options USER_LDT Please, check the FreeBSD Handbook for instructions on building a custom kernel. If you do not know where to find it, check the FreeBSD website http://www.freebsd.org/ Also, if the port finished building but did not install the aviplay program. You should consider installing the very latest qt library supporting threads. Version 2.2.3 and over should be enough. Then, try rebuilding the avifile port. Please, check the FreeBSD Handbook on updating your port tree if you need to.