Checksum mismatch while installing gperf

[Simon Cotter]

I am trying to install scipy and other python packages on my machine  
(snow leopard, intel core duo), but I am repeatedly coming up against  
the following error while trying to build one of the dependencies,  
gperf:

--->  Computing dependencies for gperf
--->  Verifying checksum(s) for gperf
Error: Checksum (md5) mismatch for gperf-3.0.4.tar.gz
Error: Checksum (sha1) mismatch for gperf-3.0.4.tar.gz
Error: Checksum (rmd160) mismatch for gperf-3.0.4.tar.gz
Error: Target org.macports.checksum returned: Unable to verify file  
checksums
Error: Status 1 encountered during processing.

I have tried to clean it and install again a few times but to no  
avail. I'm not sure if the file is corrupt or if there has been a  
stealth upgrade, or if I am being stupid, but any help is appreciated.  
Many thanks,

Simon Cotter