error during activate step

[Michael Thon]

I'm trying to write a portfile for a new package but I get an error  
during the activate step.  There's probably a bug in my portfile but  
I cant find it.  Can anyone have a quick look at this?  Here is the  
output of 'sudo port install MUMmer' and at the end of the email is  
my Portfile.  Many thanks.

DEBUG: Executing com.apple.install (MUMmer)
couldn't change working directory to "/opt/local/var/db/dports/build/ 
_Users_mike_darwinports_dports_science_MUMmer/work/destroot": no such  
file or directory
DEBUG: Executing com.apple.activate (MUMmer)
--->  Activating MUMmer 3.19_0
Error: Target com.apple.activate returned: Image error: Source file / 
opt/local/var/db/dports/software/MUMmer/3.19_0 does not appear to  
exist (cannot lstat it).  Unable to activate port MUMmer.
Warning: the following items did not execute (for MUMmer):  
com.apple.activate
Error: Status 1 encountered during processing.

--------Portfile--------
# $Id: $
PortSystem 1.0
name		MUMmer
version		3.19
revision	0
distfiles	${name}${version}.tar.gz
description	MUMmer is a system for rapidly aligning entire genomes,  
whether in \
			complete or draft form.
long_description \
MUMmer is a system for rapidly aligning entire genomes, whether in  
complete or draft \
form. For example, MUMmer 3.0 can find all 20-basepair or longer  
exact matches between \
a pair of 5-megabase genomes in 13.7 seconds, using 78 MB of memory,  
on a 2.4 GHz Linux \
desktop computer. MUMmer can also align incomplete genomes. it  
handles the 100s or 1000s \
of contigs from a shotgun \
sequencing project with ease, and will align them to another set of  
contigs or a genome \
using the NUCmer program included with the system. If the species are  
too divergent for \
DNA sequence alignment to detect similarity, then the PROmer program  
can generate \
alignments based upon the six-frame translations of both input  
sequences.

maintainers	mrt5 at mac.com
categories	science
platforms	darwin
homepage	http://mummer.sourceforge.net
master_sites	sourceforge:mummer
checksums	md5 7e0aa1c7da68c31b66fda9687171d9ff

worksrcdir		${name}${version}
use_configure   no