diff --git a/src/quest_editor/scripting/vm/VMIOStub.ts b/src/quest_editor/scripting/vm/VMIOStub.ts
index d8fdf226..6739f785 100644
--- a/src/quest_editor/scripting/vm/VMIOStub.ts
+++ b/src/quest_editor/scripting/vm/VMIOStub.ts
@@ -17,5 +17,5 @@ export class VMIOStub implements VirtualMachineIO {
     @stub winend(): void {}
     @stub mesend(): void {}
     @stub warning(msg: string, srcloc?: AsmToken): void {}
-    @stub error(msg: string, srcloc?: AsmToken): void {}
+    @stub error(err: Error, srcloc?: AsmToken): void {}
 }
diff --git a/src/quest_editor/scripting/vm/index.test.ts b/src/quest_editor/scripting/vm/index.test.ts
index bcbb2877..11eb7388 100644
--- a/src/quest_editor/scripting/vm/index.test.ts
+++ b/src/quest_editor/scripting/vm/index.test.ts
@@ -4,7 +4,8 @@ import { to_instructions } from "../../../../test/src/utils";
 
 test("basic window_msg output", () => {
     const messages = ["foo", "bar", "buz"];
-    const segments = to_instructions(`
+    const segments = to_instructions(
+        `
         .code
         0:
             arg_pushs "${messages[0]}"
@@ -14,7 +15,9 @@ test("basic window_msg output", () => {
             arg_pushs "${messages[2]}"
             add_msg
             winend
-    `, true);
+    `,
+        true,
+    );
 
     class TestIO extends VMIOStub {
         window_msg = jest.fn((msg: string) => {
@@ -27,8 +30,8 @@ test("basic window_msg output", () => {
 
         winend = jest.fn(() => {});
 
-        error = jest.fn((msg: string, loc: any) => {
-            throw msg;
+        error = jest.fn((err: Error, loc: any) => {
+            throw err;
         });
     }
 
diff --git a/src/quest_editor/scripting/vm/index.ts b/src/quest_editor/scripting/vm/index.ts
index 9c37f332..cc7ab8d3 100644
--- a/src/quest_editor/scripting/vm/index.ts
+++ b/src/quest_editor/scripting/vm/index.ts
@@ -196,6 +196,10 @@ export class VirtualMachine {
 
             return this.execute_instruction(exec, inst);
         } catch (err) {
+            if (!(err instanceof Error)) {
+                err = new Error(String(err));
+            }
+
             this.halt();
             this.io.error(err, srcloc);
 
@@ -653,7 +657,13 @@ export class VirtualMachine {
         reg1: number,
         reg2: number,
     ): void {
-        this.conditional_jump(exec, label, condition, this.get_register_signed(reg1), this.get_register_signed(reg2));
+        this.conditional_jump(
+            exec,
+            label,
+            condition,
+            this.get_register_signed(reg1),
+            this.get_register_signed(reg2),
+        );
     }
 
     private signed_conditional_jump_with_literal(
@@ -673,7 +683,13 @@ export class VirtualMachine {
         reg1: number,
         reg2: number,
     ): void {
-        this.conditional_jump(exec, label, condition, this.get_register_unsigned(reg1), this.get_register_unsigned(reg2));
+        this.conditional_jump(
+            exec,
+            label,
+            condition,
+            this.get_register_unsigned(reg1),
+            this.get_register_unsigned(reg2),
+        );
     }
 
     private unsigned_conditional_jump_with_literal(
diff --git a/src/quest_editor/scripting/vm/io.ts b/src/quest_editor/scripting/vm/io.ts
index a74f803f..83a101a3 100644
--- a/src/quest_editor/scripting/vm/io.ts
+++ b/src/quest_editor/scripting/vm/io.ts
@@ -30,7 +30,7 @@ export interface VirtualMachineMetaIO {
      * patterns that could possibly cause problems or have unintended effects.
      */
     warning(msg: string, srcloc?: AsmToken): void;
-    error(msg: string, srcloc?: AsmToken): void;
+    error(err: Error, srcloc?: AsmToken): void;
 }
 
 /**