Definitely NOT a power problem... I have found a way to install infusions manually via SSH.
If I paste the following into a text editor and replace $name with the name of the infusion and $version with the version of the infusion then copy and paste from the text editor into the ssh console then the infusion installs to my USB perfectly...
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mkdir -p /usb/tmp/infusions
wget -O /usb/tmp/infusions/mk4-module-$name-$version.tar.gz "http://cloud.wifipineapple.com/index.php?downloads&downloadModule=$name&moduleVersion=$version"
mkdir -p /usb/infusions/
rm /pineapple/infusions/usbModules
ln -s /usb/infusions /pineapple/infusions/usbInfusions
tar -xzf /usb/tmp/infusions/mk4-module-$name-$version.tar.gz -C /usb/tmp/infusions/
config=$(cat /usb/tmp/infusions/mk4-module-$name-$version/module.conf)
confName=$(echo "$config" | grep -i name | awk '{split($0,array,"=")} END{print array[2]}')
confVersion=$(echo "$config" | grep -i version | awk '{split($0,array,"=")} END{print array[2]}')
confAuthor=$(echo "$config" | grep -i author | awk '{split($0,array,"=")} END{print array[2]}')
confStartPage=$(echo "$config" | grep -i startPage | awk '{split($0,array,"=")} END{print array[2]}')
confSupportLink=$(echo "$config" | grep -i supportLink | sed 's/supportLink=//g')
mv /usb/tmp/infusions/mk4-module-$name-$version/$confName /usb/infusions/
rm -rf /usb/tmp/infusions
echo "$confName|$confVersion|$dest|$confStartPage|$confSupportLink" >> /pineapple/infusions/moduleList
opkg update && opkg install $name --dest usb
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The last line is only needed if a package is required for the infusion...
It seems to work fine for me but not an ideal solution.... when I get time I will investigate further as to why the whole procedure is not reaching this point...