What and where are my errors in this POM? - pom.xml

Question

I have tried to whrite a pom on sample application but I get a error in dependencies.
I read https://maven.apache.org/guides/index.html and https://maven.apache.org/community.html realatives article, I still can not find it.
But When I look at my pom, it contains all elements which are included in the https://maven.apache.org/guides/index.html that I need.
Given below is the pom, of my application, I can't see the error. Any body colud sugest something.
Description Resource Path Location Type
For artifact {practica:app01:null:jar}: The version cannot be empty.
org.apache.maven.artifact.InvalidArtifactRTException: For artifact {practica:app01:null:jar}: The version cannot be empty.
pom.xml /app01 line 1 Maven pom Loading Problem
Description Resource Path Location Type
Missing artifact org.springframework:spring-context:jar:${org.springframework-Version}
Thanks in advance for any help on clarifying this issue.
my pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>practica</groupId>
<artifactId>app01</artifactId>
<name>app01</name>
<packaging>jar</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<!-- Host for deploy-->
<bb-host>127.0.0.1</bb-host>
<java-version>1.7</java-version>
<org.springframework-version>3.1.1.RELEASE</org.springframework-version>
<org.aspectj-version>1.7.2</org.aspectj-version>
<org.slf4j-version>1.7.12</org.slf4j-version>
</properties>
<dependencies>
<!-- Spring -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${org.springframework-Version}</version>
<exclusions>
<!-- Exclude Commons Logging in favor of SLF4j -->
<exclusion>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${org.springframework-version}</version>
</dependency>
<!-- test -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-csv -->
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-csv</artifactId>
<version>1.5</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.camel/camel-core -->
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-core</artifactId>
<version>2.21.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.camel/camel-spring -->
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-spring</artifactId>
<version>2.21.0</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>spi-annotations</artifactId>
<version>2.21.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.camel/camel-jms -->
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-jms</artifactId>
<version>2.21.0</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-http4</artifactId>
<version>2.21.0</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-quartz</artifactId>
<version>2.21.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.activemq/activemq-all -->
<dependency>
<groupId>org.apache.activemq</groupId>
<artifactId>activemq-all</artifactId>
<version>5.15.3</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-log4j12 -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.25</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<!-- Allows the routes to be run via 'mvn camel:run' -->
<plugin>
<groupId>org.apache.camel</groupId>
<artifactId>camel-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
Thanks a lot.