You can't use the installed email client (don't even get me started) since it won't let you do anything but files that GOOGLE thinks are relevant to your phone use (this is not what I expected from them, Apple maybe...).
So, you need to download another email client like K9 and then you can download whatever you want. Stupid I know!
I have also seen this problem when attempting to download an apk file and having the Android file download fail with a status:
Cannot download. The content is not supported on this phone.
I am running unmodified Android 2.2 (Froyo) on a Motorola Droid and using the default Android browser to initiate the download.
I did some experimenting downloading the very same apk file from two different web sites. From one site the apk file downloaded and installed successfully and from the other site the Android download manager is showing the "content is not supported on this phone" error.
I took a Wire Shark packet capture to look at what is getting downloaded from the two sites. Almost everything is identical. There are a few minor HTTP reply header differences. The two main HTTP reply headers which are different and which may be related to this issue are:
Working one does not have a "Content-Disposition" header
Failing one has:
Content-Disposition: attachment; filename="BookPlayerPersonal_apk.apk
Working one has:
Failing one has:
The downloaded data appeared to be identical after the HTTP reply headers for as far as I bothered to manually compare the bytes.
I am thinking that the Android download manager must be responding badly to one of these HTTP reply header differences. I would appreciate any insights that others might have regarding this download problem.
I have determined that this issue with the Android download manager only exists in Android 2.2 (Froyo). When using previous Android versions such as 1.6 or 2.1-update1 the download manager will download and install the apk file just fine from both of the web sites.
There appears to be a change which Google introduced in Android 2.2 (Froyo) which is causing it to refuse to download and install the apk file. Apparently in 2.2 the problem is triggered by the differences in these HTTP reply headers which are returned from the web site.
Usually if you install a file manager like Astro, the browser will let you download any content. Can also depend on the browser. I use xScope which incorporates a download manager and doesn't block anything.
I reported this issue on the web site where the download was failing, and they have modified the server to no longer return a Content-Disposition header as part of the HTTP response headers returned with the download.
The .apk file now downloads and installs just fine using the default Android 2.2 browser. This definitely confirms that the problem introduced in Android 2.2 causes downloads to fail if the web server returns a Content-Disposition header.