Weird error while installing Android app?

Question

In IntelliJ IDEA I exported signed application (created a new key, etc.), entered command adb install <my_app>.apk and got an error:

1990 KB/s (745096 bytes in 0.365s)
pkg: /data/local/tmp/myapp.apk
Failure [INSTALL_PARSE_FAILED_UNEXPECTED_EXCEPTION]

Google doesn't seem to know about this error. I found the solution where application version in Manifest file was not an integer, but this is not the case with me.

Could I be making a mistake during the creation of new sign key???

EDIT: Here is my Manifest file.

<?xml version="1.0" encoding="utf-8"?>
<manifest
        xmlns:android="http://schemas.android.com/apk/res/android"
        package="org.example.app"
        android:versionCode="1"
        android:versionName="1.0"
        >
    <application
            android:icon="@drawable/icon"
            android:label="@string/app_name"
            >
        <activity
                android:name=".App"
                android:label="@string/app_name"
                >
            <intent-filter>
                <action
                        android:name="android.intent.action.MAIN"/>
                <category
                        android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>

        </activity>

        <activity
                android:label="@string/about"
                android:name="About"
                ></activity>
        <activity
                android:label="@string/preference"
                android:name="Preference"
                ></activity>
        <activity
                android:name="Empl"
                android:label="@string/empl"
                ></activity>
    </application>
    <uses-sdk
            android:minSdkVersion="8"/>

</manifest> 

Answer 1

After all it was a mistake in the manifest file. This line made it

<uses-sdk android:minSdkVersion="8"/>

I tried to deploy Android 2.2 app to a mobile phone with Android 2.1. The other project (the test one) was created in IntelliJ which does not force any version by default.

After I deleted the line or changed version to 7, app installed with no problems.

So rookie mistake :ashamed:.