diff --git a/ext/oci8/bind.c b/ext/oci8/bind.c
index 032a7584..f1069f85 100644
--- a/ext/oci8/bind.c
+++ b/ext/oci8/bind.c
@@ -383,7 +383,7 @@ static sb4 in_bind_callback(void *ictxp, OCIBind *bindp, ub4 iter, ub4 index, vo
 
     if (cb->tail == &cb->head) {
         /* empty string */
-        *bufpp = "";
+        *bufpp = (void *)"";
         *alenp = 0;
         *piecep = OCI_ONE_PIECE;
     } else {
diff --git a/ext/oci8/oci8.h b/ext/oci8/oci8.h
index 6674e912..03553eb7 100644
--- a/ext/oci8/oci8.h
+++ b/ext/oci8/oci8.h
@@ -424,6 +424,7 @@ void *oci8_check_typeddata(VALUE obj, const oci8_handle_data_type_t *data_type,
 extern VALUE eOCIException;
 extern VALUE eOCIBreak;
 void Init_oci8_error(void);
+NORETURN(void oci8_do_raise(OCIError *errhp, sword status, OCIStmt *stmthp, const char *file, int line));
 NORETURN(void oci8_do_env_raise(OCIEnv *envhp, sword status, int free_envhp, const char *file, int line));
 NORETURN(void oci8_do_raise_init_error(const char *file, int line));
 sb4 oci8_get_error_code(OCIError *errhp);
diff --git a/ext/oci8/oraconf.rb b/ext/oci8/oraconf.rb
index 7c45927f..d2975200 100644
--- a/ext/oci8/oraconf.rb
+++ b/ext/oci8/oraconf.rb
@@ -995,16 +995,16 @@ def initialize(inc_dir, lib_dir)
     init
 
     if RUBY_PLATFORM =~ /mswin32|mswin64|cygwin|mingw32|bccwin32/ # when Windows
-      unless File.exist?("#{ic_dir}/sdk/lib/msvc/oci.lib")
+      unless File.exist?("#{lib_dir}/sdk/lib/msvc/oci.lib")
         raise <<EOS
 Could not compile with Oracle instant client.
-#{ic_dir}/sdk/lib/msvc/oci.lib could not be found.
+#{lib_dir}/sdk/lib/msvc/oci.lib could not be found.
 EOS
         raise 'failed'
       end
       @cflags = " \"-I#{inc_dir}\""
       @cflags += " -D_int64=\"long long\"" if RUBY_PLATFORM =~ /cygwin|mingw32/
-      @libs = get_libs("#{ic_dir}/sdk/lib")
+      @libs = get_libs("#{lib_dir}/sdk/lib")
       ld_path = nil
     else
       @cflags = " -I#{inc_dir}"
diff --git a/lib/oci8.rb b/lib/oci8.rb
index b21f1549..a81d84a7 100644
--- a/lib/oci8.rb
+++ b/lib/oci8.rb
@@ -11,8 +11,11 @@
   # Cygwin manages environment variables by itself.
   # They don't synchroize with Win32's ones.
   # This set some Oracle's environment variables to win32's enviroment.
-  require 'Win32API'
-  win32setenv = Win32API.new('Kernel32.dll', 'SetEnvironmentVariableA', 'PP', 'I')
+  require 'fiddle'
+  win32setenv = Fiddle::Function.new( Fiddle.dlopen('Kernel32.dll')['SetEnvironmentVariableA'],
+                                        [Fiddle::TYPE_VOIDP,Fiddle::TYPE_VOIDP],
+                                        Fiddle::TYPE_INT )
+
   ['NLS_LANG', 'TNS_ADMIN', 'LOCAL'].each do |name|
     val = ENV[name]
     win32setenv.call(name, val && val.dup)
diff --git a/setup.rb b/setup.rb
index 84477911..3187acd3 100644
--- a/setup.rb
+++ b/setup.rb
@@ -286,7 +286,7 @@ def ConfigTable.load
 
   def initialize_from_table
     @table = {}
-    DESCRIPTER.each do |k, (default, vname, desc, default2)|
+    DESCRIPTER.each do |k, (default, *)|
       @table[k] = default
     end
   end