diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..3b57a5e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,10 @@
+scriptedamigaemulator.js
+scriptedamigaemulator.js.map
+*.adf
+db/index.htm
+db/aros-amiga-m68k-ext.bin
+db/aros-amiga-m68k-rom.bin
+db/demos/index.htm
+db/demos_aga/index.htm
+db/games/index.htm
+db/tools/index.htm
\ No newline at end of file
diff --git a/index.js b/index.js
index 0fc4e27..3b4aca7 100644
--- a/index.js
+++ b/index.js
@@ -489,8 +489,10 @@ function saee2text(err) {
 		case SAEE_NotRunning:					return "The emulator is not running.";
 		case SAEE_NoTimer:						return "No timing-functions avail. Please upgrade your browser.";
 		case SAEE_NoMemory:						return "Out of memory.";
-		case SAEE_Internal:						return "Internal emulator error.";
+		case SAEE_Assert:							return "Assertiation failed.";	
+		case SAEE_Internal:						return "Internal emulator error.";	
 		case SAEE_Config_Invalid:				return "Invalid configuration.";
+		case SAEE_Config_Compressed:			return "A ZIP file was detected. Compressed files are not yet supported.";
 		case SAEE_CPU_Internal:					return "Internal CPU-error.";
 		case SAEE_CPU_Requires68020:			return "The selected kickstart-rom does require a 68020 and 32bit address-space";
 		case SAEE_CPU_Requires680EC20:		return "The selected kickstart-rom does require a 68020.";
diff --git a/sae/amiga.js b/sae/amiga.js
index 972fbdb..eaee448 100644
--- a/sae/amiga.js
+++ b/sae/amiga.js
@@ -68,6 +68,7 @@ const SAEE_Assert = 5;
 const SAEE_Internal = 6;
 
 const SAEE_Config_Invalid = 10;
+const SAEE_Config_Compressed = 11;
 
 const SAEE_CPU_Internal = 20;
 const SAEE_CPU_Requires68020 = 21;
diff --git a/sae/utils.js b/sae/utils.js
index f45322d..8c689ec 100644
--- a/sae/utils.js
+++ b/sae/utils.js
@@ -493,6 +493,14 @@ function SAEF_ZFile_fopen_file(file) {
 		l.datasize = file.size;
 		l.allocsize = file.size; //OWN
 
+		var magic = ((l.data[0] << 24) | (l.data[1] << 16) | (l.data[2] << 8) | (l.data[3])) >>> 0;
+
+		SAEF_log("SAEF_ZFile_fopen_file() opening '%s', %d/%d bytes, crc32 0x%08x, magic %08x",
+			l.name, l.size, l.data.length, file.crc32 !== false ? file.crc32 : 0, magic);
+
+		if (magic == 0x04034B50 || magic == 0x504B0304)
+			SAEF_fatal(SAEE_Config_Compressed, "A ZIP file was detected. Compressed files are not yet supported.");
+
 		//if (l.data[0] == 68 && l.data[1] == 77 && l.data[2] == 83 && l.data[3] == 33) { /* DMS! */
 		if (SAEF_CompareArray(l.data, SAEF_String2Array("DMS!"), 4) == 0) {
 			var dms = new SAEO_DMS();