Under the hood wsimport utinilty uses JAXB compiler, so actualy error is relevant to JAXB. As stated in JAXB guide, you have two options - use schemabindings or factoryMethod customization, though that depends on your WSLD and it might be not possible. Another option would be to rename conflicting types in your WSDL document.
Based on comment below lets assume that this is your schema:
<?xml version="1.0" encoding="utf-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:complexType name="Exception">
<xs:sequence>
<xs:element minOccurs="0" name="Exception" nillable="true" type="xs:anyType"/>
</xs:sequence>
</xs:complexType>
<xs:element name="Exception">
<xs:complexType>
<xs:sequence>
<xs:element minOccurs="0" name="Exception" nillable="true" type="Exception"/>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>
To gernerate same errors you might run xjc compiler:
/bin/xjc.sh schema.xsd
As mentioned above easyest way to fix this issue would be to rename complex type or element name. But to make things more interesting you might define JAXB customization
<jaxb:bindings xmlns:jaxb="http://java.sun.com/xml/ns/jaxb"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
version="1.0">
<jaxb:bindings schemaLocation="schema.xsd">
<jaxb:bindings node="//xs:complexType[@name='Exception']">
<jaxb:factoryMethod name="TypeException"/>
<jaxb:class name="TypeException" />
</jaxb:bindings>
</jaxb:bindings>
</jaxb:bindings>
And try once more:
/bin/xjc.sh -b binding.xml schema.xsd
Same binding might be supplied to wsimport utility:
wsimport myService.wsdl -b binding.xml