diff --git a/src/i18n/index.ts b/src/i18n/index.ts
index c91bd2e..e48618c 100644
--- a/src/i18n/index.ts
+++ b/src/i18n/index.ts
@@ -47,6 +47,10 @@ export class I18nService {
     let value: string | TranslationData = translations;
 
     for (const key of keys) {
+      if (typeof value === 'string') {
+        // If we hit a string before traversing all keys, the path is invalid
+        break;
+      }
       value = value?.[key];
       if (value === undefined) {
         // Fallback to default locale if key not found
diff --git a/src/routes/admin.ts b/src/routes/admin.ts
index 4a55a8d..3bb7cc8 100644
--- a/src/routes/admin.ts
+++ b/src/routes/admin.ts
@@ -74,7 +74,16 @@ type AuthMiddleware = (req: Request, res: Response, next: NextFunction) => void;
 export default (
   locationModel: Location,
   profanityWordModel: ProfanityWord,
-  profanityFilter: ProfanityFilterService,
+  profanityFilter: ProfanityFilterService | {
+    containsProfanity(): boolean;
+    analyzeProfanity(text: string): any;
+    filterProfanity(text: string): string;
+    addCustomWord(word: string, severity: string, category: string, createdBy?: string): Promise<any>;
+    removeCustomWord(wordId: number): Promise<any>;
+    updateCustomWord(wordId: number, updates: any): Promise<any>;
+    getCustomWords(): Promise<any[]>;
+    loadCustomWords(): Promise<void>;
+  },
   authenticateAdmin: AuthMiddleware
 ): Router => {
   const router = express.Router();
diff --git a/src/routes/locations.ts b/src/routes/locations.ts
index 6c97fff..61fc2d2 100644
--- a/src/routes/locations.ts
+++ b/src/routes/locations.ts
@@ -14,7 +14,11 @@ interface LocationPostRequest extends Request {
 }
 
 
-export default (locationModel: Location, profanityFilter: ProfanityFilterService): Router => {
+export default (locationModel: Location, profanityFilter: ProfanityFilterService | {
+  containsProfanity(): boolean;
+  analyzeProfanity(text: string): any;
+  filterProfanity(text: string): string;
+}): Router => {
   const router = express.Router();
 
   // Rate limiting for location submissions to prevent abuse
@@ -220,7 +224,7 @@ export default (locationModel: Location, profanityFilter: ProfanityFilterService
             details: {
               severity: analysis.severity,
               wordCount: analysis.count,
-              detectedCategories: [...new Set(analysis.matches.map(m => m.category))]
+              detectedCategories: [...new Set(analysis.matches.map((m: any) => m.category))]
             }
           });
           return;
diff --git a/src/server.ts b/src/server.ts
index 587d9bf..89e24a6 100644
--- a/src/server.ts
+++ b/src/server.ts
@@ -1,3 +1,4 @@
+/// <reference path="./types/index.d.ts" />
 import dotenv from 'dotenv';
 import express, { Request, Response, NextFunction, Application } from 'express';
 import cors from 'cors';
@@ -88,23 +89,15 @@ function createFallbackFilter(): FallbackFilter {
     filterProfanity: (text: string): string => text || '',
 
     // Database management methods used by admin routes
-    addCustomWord: async (word: string, severity: string, category: string, createdBy?: string) => ({
-      id: null,
-      word: word || null,
-      severity: severity || null,
-      category: category || null,
-      createdBy: createdBy || null,
-      success: false,
-      error: 'Profanity filter not available - please check server configuration'
-    }),
-    removeCustomWord: async () => ({
-      success: false,
-      error: 'Profanity filter not available - please check server configuration'
-    }),
-    updateCustomWord: async () => ({
-      success: false,
-      error: 'Profanity filter not available - please check server configuration'
-    }),
+    addCustomWord: async (): Promise<ProfanityWord> => {
+      throw new Error('Profanity filter not available - please check server configuration');
+    },
+    removeCustomWord: async (): Promise<{ deleted: boolean; changes: number }> => {
+      throw new Error('Profanity filter not available - please check server configuration');
+    },
+    updateCustomWord: async (): Promise<ProfanityWord> => {
+      throw new Error('Profanity filter not available - please check server configuration');
+    },
     getCustomWords: async (): Promise<ProfanityWord[]> => [],
     loadCustomWords: async (): Promise<void> => {},