The GoogleMaps curse: BaseTileRequest failed - google-maps

Question

Though I've been reading the StackOverflow forums for years, it's the first time I post here. I know the problem I'm talking about has been asked before, but, as I've seen, it seems that there's no clear answer to it, so I'm posting my case as detailed as I can to see if someone can help me understand what I'm doing wrong before I jump off a cliff.
The "Map doesn't work in debug mode" myth: is it true? I've read more than once that, while using the debug API key, the map doesn't load properly, but once the app is released and signed in to the market, the problem disappears... Is this so? May I test a half-functioning app assuming that the map works well and then uploaded it to the market hoping that it will work as expected? (Please, say "yes", and release me from this living hell of tiles that don't load!)
What I've done with my app:
Used the "keytool" command to list the certificate fingerprint of my keystore:
$ keytool -list -alias androiddebugkey -keystore ./.android/debug.keystore -storepass android -keypass android
Created an API project and generated an API key using the certificate fingerprint from the step above.
Added the API key and the permissions on the AndroidManifest.xml:
<uses-feature
android:glEsVersion="0x00020000"
android:required="true"/>
<permission
android:name="com.mycompany.test1.permission.MAPS_RECEIVE"
android:protectionLevel="signature" />
<uses-permission android:name="com.mycompany.test1.permission.MAPS_RECEIVE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
(...)
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="AItaSyDGE2yil3tCr9NP45QVDPfmRUP-gNv7uLY" />
Added a map on the XML layout of my activity:
<com.google.android.maps.MapView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/mapView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:enabled="true"
android:clickable="true"
android:apiKey="AItaSyDGE2yil3tCr9NP45QVDPfmRUP-gNv7uLY"
/>
<!-- Though the Google page says to use the following code, Eclipse shows an error referring to the "xmlns" tag and it can't be compiled: -->
<!--
<fragment
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.google.android.gms.maps.MapFragment"/>
-->
I've tried compiling in the emulator using Google APIs, using Android 4.x, using three real devices with Android 2.3, 4.0 and 4.2, exporting the project's .apk and installing the APK on the device directly from the USB card, but the behavior is always the same: when trying to show the map, LogCat fills with the following error:
IOException processing: 26
java.io.IOException: Server returned: 3
at android_maps_conflict_avoidance.com.google.googlenav.map.BaseTileRequest.readResponseData(BaseTileRequest.java:115)
at android_maps_conflict_avoidance.com.google.googlenav.map.MapService$MapTileRequest.readResponseData(MapService.java:1473)
at android_maps_conflict_avoidance.com.google.googlenav.datarequest.DataRequestDispatcher.processDataRequest(DataRequestDispatcher.java:1117)
at android_maps_conflict_avoidance.com.google.googlenav.datarequest.DataRequestDispatcher.serviceRequests(DataRequestDispatcher.java:994)
at android_maps_conflict_avoidance.com.google.googlenav.datarequest.DataRequestDispatcher$DispatcherServer.run(DataRequestDispatcher.java:1702)
at java.lang.Thread.run(Thread.java:856)
Anybody knows what can be happening? I've followed the Google guide like a thousand times, regenerated my API key, checked my manifest, tested the app on the emulator, on devices, etc. and NOTHING changed anything! As I've said previously in this post, I've read that the maps are, simply, not able to be tested when "testing" the app, so one should wait until the app is published in the market to see them working... However, it sounds me weird! Any ideas?
Thanks in advance for your time and effort! :)