An error occurred after upgrade soapUI to 5.1.1

We want to check JSON schema in his scripts. So we use some jar packages such as jackson-databind-2.2.3.jar and json-schema-validator-2.2.3.jar. We put these jar packages under D:\Program Files\SmartBear\SoapUI-Pro-5.1.1\bin\ext before SoapUI 5.0, it works fine. But it does not work after upgrade SoapUI 5.1. But it works when put them under D:\Program Files\SmartBear\SoapUI-Pro-5.1.1\jre\lib\ext.

Error message:
"WRITE_BIGDECIMAL_AS_PLAIN" or
"Could not initialize class com.github.fge.jsonschema.SchemaVersion"


The jar packages list as follows:
access-bridge-64.jar
activation-1.1.jar
btf-1.2.jar
dnsns.jar
dns_sd.jar
guava-16.0.1.jar
jaccess.jar
jackson-annotations-2.2.3.jar
jackson-core-2.2.3.jar
jackson-coreutils-1.6.jar
jackson-databind-2.2.3.jar
jfxrt.jar
joda-time-2.3.jar
jopt-simple-4.6.jar
json-schema-core-1.2.1.jar
json-schema-validator-2.2.3.jar
jsr305-2.0.1.jar
libphonenumber-6.0.jar
localedata.jar
mailapi-1.4.3.jar
msg-simple-1.1.jar
nzjdbc-7.0.2.jar
rhino-1.7R4.jar
sunec.jar
sunjce_provider.jar
sunmscapi.jar
uri-template-0.9.jar
zipfs.jar