[7.951][BUG][OPEN] Unable to Download .exe files

Hi 
since the .951 release I have been getting "Unsupported archive format encountered" errors whenever I download an *.exe file. see pics for examples.
Below is a copy of the content filter output.
Mark

2010:06:29-14:52:27 roxy73 httpproxy[11176]: id="0003" severity="info" sys="SecureWeb" sub="http" request="0xa4229a8" function="avira_error_cb" file="avirascanner.c" line="141" message="name localized/uninstall/helper.exe, category 2, level 0, code 28 (Unsupported archive format encountered)"
2010:06:29-14:52:27 roxy73 httpproxy[11176]: id="0056" severity="info" sys="SecureWeb" sub="http" name="web request blocked, error while scanning" action="block" method="GET" srcip="172.16.20.9" dstip="130.89.149.173" user="" statuscode="500" cached="0" profile="REF_DefaultHTTPProfile (Default Proxy)" filteraction="REF_DefaultHTTPCFFAction (Default content filter action)" size="4713" time="211628 ms" request="0xa4229a8" url="mozilla3.snt.utwente.nl/.../octet-stream" engine="Astaro-AV"
2010:06:29-14:55:16 roxy73 httpproxy[11176]: id="0003" severity="info" sys="SecureWeb" sub="http" request="(nil)" function="sc_check_servers" file="scr_scanner.c" line="724" message="server 'cffs10.astaro.com' access time: 46ms"
2010:06:29-14:55:16 roxy73 httpproxy[11176]: id="0003" severity="info" sys="SecureWeb" sub="http" request="(nil)" function="sc_check_servers" file="scr_scanner.c" line="724" message="server 'cffs08.astaro.com' access time: 334ms"
2010:06:29-14:55:16 roxy73 httpproxy[11176]: id="0003" severity="info" sys="SecureWeb" sub="http" request="(nil)" function="sc_check_servers" file="scr_scanner.c" line="724" message="server 'cffs03.astaro.com' access time: 448ms"
2010:06:29-14:55:17 roxy73 httpproxy[11176]: id="0003" severity="info" sys="SecureWeb" sub="http" request="(nil)" function="sc_check_servers" file="scr_scanner.c" line="724" message="server 'cffs07.astaro.com' access time: 496ms"