Error when running sp_BlitzFirst from First-Responder-Kit-20170307

when I run

EXEC sp_BlitzFirst @expertmode=1

I get

Setting up configuration variables
Warning: The join order has been enforced because a local join hint is used.
Now starting diagnostic analysis
Capturing first pass of wait stats, perfmon counters, file stats
Beginning investigatory queries
Msg 137, Level 15, State 2, Line 8
Must declare the scalar variable "@LineFeed".
Msg 102, Level 15, State 1, Line 9
Incorrect syntax near ','.
Msg 102, Level 15, State 1, Line 10
Incorrect syntax near ','.
Msg 8169, Level 16, State 1, Line 11
Conversion failed when converting from a character string to uniqueidentifier.
Msg 102, Level 15, State 1, Line 11
Incorrect syntax near ' AS HowToStopIt,
                (SELECT TOP 1 query_plan FROM sys.dm_exec_query_plan(r.plan_handle)) AS QueryPlan,
           '.
Msg 105, Level 15, State 1, Line 27
Unclosed quotation mark after the character string ' AND tBlocked.wait_duration_ms > 30000;'.
Finished running investigatory queries
Waiting to match @Seconds parameter
Capturing second pass of wait stats, perfmon counters, file stats
Analyzing changes between first and second passes of DMVs
Analysis finished, outputting results

This is from First-Responder-Kit-20170307

The SQL Server version and build I have is:

Microsoft SQL Server 2012 (SP3-CU7) (KB3205051) - 11.0.6579.0 (X64)   Dec 22 2016 11:18:09   Copyright (c) Microsoft Corporation  Developer Edition (64-bit) on Windows NT 6.1 <X64> (Build 7601: Service Pack 1)