1. Try the gapps I linked to
2. If that doesn't work, find a signed version of maps. Uninstall maps from Play (if it's installed at all) and install the signed version you downloaded from the net. Now update at Play.
3. If #2 doesn't work:
a.) connect your phone to PC and open command prompt
b.) adb shell chmod 666 /data/system/packages.xml
c.) adb pull /data/system/packages.xml
d.) open packages.xml and find the maps block
e.) comment out (or delete) shared user name code from maps block in packages.xml so it looks like this:
PHP Code:
<!--<shared-user name="com.navngo" userId="10000">
<sigs count="1">
<cert index="4" />
</sigs>
<perms>
<item name="android.permission.READ_PHONE_STATE" />
<item name="android.permission.DISABLE_KEYGUARD" />
<item name="android.permission.INTERNET" />
<item name="android.permission.WRITE_EXTERNAL_STORAGE" />
<item name="android.permission.ACCESS_FINE_LOCATION" />
<item name="android.permission.ACCESS_LOCATION_EXTRA_COMMANDS" />
<item name="android.permission.ACCESS_COARSE_LOCATION" />
<item name="android.permission.READ_CONTACTS" />
<item name="android.permission.WRITE_CONTACTS" />
<item name="android.permission.ACCESS_NETWORK_STATE" />
<item name="android.permission.WAKE_LOCK" />
<item name="android.permission.MODIFY_AUDIO_SETTINGS" />
</perms>
</shared-user>-->
f. adb push packages.xml /data/system
g. adb shell rm /data/dalvik-cache/*
h. adb reboot
i. attempt the install again.
The reason this is happening is that whoever authored the firmware didn't do a clean job of it.