diff --git a/src/base_media_base.h b/src/base_media_base.h
--- a/src/base_media_base.h
+++ b/src/base_media_base.h
@@ -108,10 +108,11 @@ struct BaseSet {
 	 * Read the set information from a loaded ini.
 	 * @param ini      the ini to read from
 	 * @param path     the path to this ini file (for filenames)
+	 * @param full_filename the full filename of the loaded file (for error reporting purposes)
 	 * @param allow_empty_filename empty filenames are valid
 	 * @return true if loading was successful.
 	 */
-	bool FillSetDetails(IniFile *ini, const char *path, bool allow_empty_filename = true);
+	bool FillSetDetails(IniFile *ini, const char *path, const char *full_filename, bool allow_empty_filename = true);
 
 	/**
 	 * Get the description for the given ISO code.
@@ -238,7 +239,7 @@ enum GraphicsFileType {
 struct GraphicsSet : BaseSet<GraphicsSet, MAX_GFT, DATA_DIR> {
 	PaletteType palette;       ///< Palette of this graphics set
 
-	bool FillSetDetails(struct IniFile *ini, const char *path);
+	bool FillSetDetails(struct IniFile *ini, const char *path, const char *full_filename);
 };
 
 /** All data/functions related with replacing the base graphics. */
@@ -276,7 +277,7 @@ struct MusicSet : BaseSet<MusicSet, NUM_
 	byte track_nr[NUM_SONGS_AVAILABLE];
 	byte num_available;
 
-	bool FillSetDetails(struct IniFile *ini, const char *path);
+	bool FillSetDetails(struct IniFile *ini, const char *path, const char *full_filename);
 };
 
 /** All data/functions related with replacing the base music */
diff --git a/src/base_media_func.h b/src/base_media_func.h
--- a/src/base_media_func.h
+++ b/src/base_media_func.h
@@ -25,12 +25,13 @@ template <class Tbase_set> /* static */ 
 #define fetch_metadata(name) \
 	item = metadata->GetItem(name, false); \
 	if (item == NULL || StrEmpty(item->value)) { \
-		DEBUG(grf, 0, "Base " SET_TYPE "set detail loading: %s field missing", name); \
+		DEBUG(grf, 0, "Base " SET_TYPE "set detail loading: %s field missing.", name); \
+		DEBUG(grf, 0, "  Is %s readable for the user running OpenTTD?", full_filename); \
 		return false; \
 	}
 
 template <class T, size_t Tnum_files, Subdirectory Tsubdir>
-bool BaseSet<T, Tnum_files, Tsubdir>::FillSetDetails(IniFile *ini, const char *path, bool allow_empty_filename)
+bool BaseSet<T, Tnum_files, Tsubdir>::FillSetDetails(IniFile *ini, const char *path, const char *full_filename, bool allow_empty_filename)
 {
 	memset(this, 0, sizeof(*this));
 
@@ -70,7 +71,7 @@ bool BaseSet<T, Tnum_files, Tsubdir>::Fi
 		/* Find the filename first. */
 		item = files->GetItem(BaseSet<T, Tnum_files, Tsubdir>::file_names[i], false);
 		if (item == NULL || (item->value == NULL && !allow_empty_filename)) {
-			DEBUG(grf, 0, "No " SET_TYPE " file for: %s", BaseSet<T, Tnum_files, Tsubdir>::file_names[i]);
+			DEBUG(grf, 0, "No " SET_TYPE " file for: %s (in %s)", BaseSet<T, Tnum_files, Tsubdir>::file_names[i], full_filename);
 			return false;
 		}
 
@@ -88,7 +89,7 @@ bool BaseSet<T, Tnum_files, Tsubdir>::Fi
 		/* Then find the MD5 checksum */
 		item = md5s->GetItem(filename, false);
 		if (item == NULL) {
-			DEBUG(grf, 0, "No MD5 checksum specified for: %s", filename);
+			DEBUG(grf, 0, "No MD5 checksum specified for: %s (in %s)", filename, full_filename);
 			return false;
 		}
 		char *c = item->value;
@@ -101,7 +102,7 @@ bool BaseSet<T, Tnum_files, Tsubdir>::Fi
 			} else if ('A' <= *c && *c <= 'F') {
 				j = *c - 'A' + 10;
 			} else {
-				DEBUG(grf, 0, "Malformed MD5 checksum specified for: %s", filename);
+				DEBUG(grf, 0, "Malformed MD5 checksum specified for: %s (in %s)", filename, full_filename);
 				return false;
 			}
 			if (i % 2 == 0) {
@@ -155,7 +156,7 @@ bool BaseMedia<Tbase_set>::AddFile(const
 		*path = '\0';
 	}
 
-	if (set->FillSetDetails(ini, path)) {
+	if (set->FillSetDetails(ini, path, filename)) {
 		Tbase_set *duplicate = NULL;
 		for (Tbase_set *c = BaseMedia<Tbase_set>::available_sets; c != NULL; c = c->next) {
 			if (strcmp(c->name, set->name) == 0 || c->shortname == set->shortname) {
diff --git a/src/gfxinit.cpp b/src/gfxinit.cpp
--- a/src/gfxinit.cpp
+++ b/src/gfxinit.cpp
@@ -202,9 +202,9 @@ void GfxLoadSprites()
 	GfxInitPalettes();
 }
 
-bool GraphicsSet::FillSetDetails(IniFile *ini, const char *path)
+bool GraphicsSet::FillSetDetails(IniFile *ini, const char *path, const char *full_filename)
 {
-	bool ret = this->BaseSet<GraphicsSet, MAX_GFT, DATA_DIR>::FillSetDetails(ini, path, false);
+	bool ret = this->BaseSet<GraphicsSet, MAX_GFT, DATA_DIR>::FillSetDetails(ini, path, full_filename, false);
 	if (ret) {
 		IniGroup *metadata = ini->GetGroup("metadata");
 		IniItem *item;
@@ -212,7 +212,7 @@ bool GraphicsSet::FillSetDetails(IniFile
 		fetch_metadata("palette");
 		this->palette = (*item->value == 'D' || *item->value == 'd') ? PAL_DOS : PAL_WINDOWS;
 	}
-	return true;
+	return ret;
 }
 
 
diff --git a/src/music.cpp b/src/music.cpp
--- a/src/music.cpp
+++ b/src/music.cpp
@@ -57,9 +57,9 @@ template <class Tbase_set>
 	return BaseMedia<Tbase_set>::used_set != NULL;
 }
 
-bool MusicSet::FillSetDetails(IniFile *ini, const char *path)
+bool MusicSet::FillSetDetails(IniFile *ini, const char *path, const char *full_filename)
 {
-	bool ret = this->BaseSet<MusicSet, NUM_SONGS_AVAILABLE, GM_DIR>::FillSetDetails(ini, path);
+	bool ret = this->BaseSet<MusicSet, NUM_SONGS_AVAILABLE, GM_DIR>::FillSetDetails(ini, path, full_filename);
 	if (ret) {
 		this->num_available = 0;
 		IniGroup *names = ini->GetGroup("names");
@@ -93,5 +93,5 @@ bool MusicSet::FillSetDetails(IniFile *i
 			this->num_available++;
 		}
 	}
-	return true;
+	return ret;
 }