DB Pro 2005: System.ArgumentException: Unable to create AST

I am trying to do a Schema Compare between my project and the dev database and VS 2005 crashes when it gets to the part "Comparing Databases". I can compare the test database to the dev database, but as soon as my project is involved it crashes.

After disabling all Add Ins I discovered SQL Prompt v4.0 was the offender. With it enabled schema compares fail, with it disabled they work.

[Pid=7532;Tid=1;Time=14:38:47]: Verbose: 8: Entering SchemaCompareVirtualTreeControl.Initialize(...): sourceDBName = MyDB(Source Project), targetDBName = devserver.MyDB.dbo (Target Database).
[Pid=7532;Tid=1;Time=14:38:47]: Verbose: 8: Entering SchemaCompareTree constructor.
[Pid=7532;Tid=1;Time=14:38:47]: Verbose: 8: Entering SchemaCompareEditorPane.PopulateStatusStrip().
[Pid=7532;Tid=1;Time=14:38:47]: Verbose: 8: Entering SchemaCompareEditorPane.UpdateAndShowSyncScript(bool).
[Pid=7532;Tid=12;Time=14:39:22]: Verbose: 4: Entering DataPackage.Sqm (getter).
[Pid=7532;Tid=12;Time=14:39:22]: Warning: 64: Exception Caught in JobManager.RunImpl(object): System.ArgumentException: Unable to create AST Node Type: 'antlr.CommonAST' ---> System.InvalidCastException: Unable to cast object of type 'antlr.CommonAST' to type 'antlr.collections.AST'.
at antlr.ASTFactory.createFromNodeTypeObject(Type nodeTypeObject)
--- End of inner exception stack trace ---
at antlr.ASTFactory.createFromNodeTypeObject(Type nodeTypeObject)
at antlr.ASTFactory.createFromNodeType(Int32 nodeTypeIndex)
at antlr.ASTFactory.create(IToken tok)
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.constant()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.subExpression()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.mulExpression()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.addExpression()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.expression()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.subSearchCondition()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.searchConditionNOT()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.searchConditionAND()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.searchCondition()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.subExpression()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.mulExpression()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.addExpression()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.expression()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.subSearchCondition()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.searchConditionNOT()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.searchConditionAND()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.searchCondition()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ConstraintParser.parseExpression()
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.ParserHelper.TextEqualWithExtraParantheses(String text1, String text2, Options options)
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.Default.DefaultTextEquals(String text, String targetText, Options options)
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.Field.Equals(Field targetField, Options options)
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.Table.Equals(IDatabaseObject targetObject, Options options)
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.Database.CompareWith(Differences differences, IDatabaseObjects objects, IDatabaseObjects targetObjects, Options options, Int32 targetDBMajorVersion, Int64 totalCount, Int64& count, Int32& percentage)
at Microsoft.VisualStudio.TeamSystem.Data.Compare.Schema.Database.CompareWith(Database targetDatabase, Options options)
at Microsoft.VisualStudio.TeamSystem.Data.SchemaAndDataCompare.UI.Editors.SchemaCompareDataPopulationJob.Run()
at Microsoft.VisualStudio.TeamSystem.Data.Common.Threading.JobManager.JobBase.<Microsoft.VisualStudio.TeamSystem.Data.Common.Threading.JobManager.IManageableJob.RunImpl>b__0(Object state)
at System.Threading.ExecutionContext.runTryCode(Object userData)
at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at Microsoft.VisualStudio.TeamSystem.Data.Common.Threading.JobManager.JobBase.Microsoft.VisualStudio.TeamSystem.Data.Common.Threading.JobManager.IManageableJob.RunImpl(Object dummyArg)