diff --git a/h5pyd/_hl/files.py b/h5pyd/_hl/files.py
index ee8dbf2..e811b7b 100644
--- a/h5pyd/_hl/files.py
+++ b/h5pyd/_hl/files.py
@@ -15,6 +15,7 @@
 import os
 import time
 import json
+import pathlib
 
 from .objectid import GroupID
 from .group import Group
@@ -203,6 +204,11 @@ def __init__(
             if not domain:
                 raise IOError(400, "no domain provided")
 
+            domain_path = pathlib.PurePath(domain)
+            if isinstance(domain_path, pathlib.PureWindowsPath):
+                # Standardize path root to POSIX-style path
+                domain = '/' + '/'.join(domain_path.parts[1:])
+
             if domain[0] != "/":
                 raise IOError(400, "relative paths are not valid")
 
diff --git a/h5pyd/_hl/h5type.py b/h5pyd/_hl/h5type.py
index fed3da7..eb2afe2 100644
--- a/h5pyd/_hl/h5type.py
+++ b/h5pyd/_hl/h5type.py
@@ -142,7 +142,6 @@ def special_dtype(**kwds):
     name, val = kwds.popitem()
 
     if name == 'vlen':
-
         return np.dtype('O', metadata={'vlen': val})
 
     if name == 'enum':
@@ -441,6 +440,10 @@ def getTypeItem(dt):
             type_info['length'] = 'H5T_VARIABLE'
             type_info['charSet'] = 'H5T_CSET_UTF8'
             type_info['strPad'] = 'H5T_STR_NULLTERM'
+        elif vlen_check == np.int32:
+            type_info['class'] = 'H5T_VLEN'
+            type_info['size'] = 'H5T_VARIABLE'
+            type_info['base'] = 'H5T_STD_I32'
         elif vlen_check in (int, np.int64):
             type_info['class'] = 'H5T_VLEN'
             type_info['size'] = 'H5T_VARIABLE'
diff --git a/h5pyd/_hl/httpconn.py b/h5pyd/_hl/httpconn.py
index cb161ba..a9bbeba 100644
--- a/h5pyd/_hl/httpconn.py
+++ b/h5pyd/_hl/httpconn.py
@@ -571,7 +571,9 @@ def PUT(self, req, body=None, format="json", params=None, headers=None):
             # binary write
             data = body
         else:
+            headers["Content-Type"] = "application/json"
             data = json.dumps(body)
+
         self.log.info("PUT: {} format: {} [{} bytes]".format(req, format, len(data)))
 
         try:
diff --git a/test/apps/load_files.py b/test/apps/load_files.py
index 2c58934..abf1303 100644
--- a/test/apps/load_files.py
+++ b/test/apps/load_files.py
@@ -15,7 +15,7 @@
 import sys
 import config
 import h5pyd
-
+from platform import system
 #
 # Main
 #
@@ -60,9 +60,19 @@
             # wget from S3
             http_path = test_file_http_path + filename
             print("downloading:", http_path)
-            rc = os.system(f"wget -q https://s3.amazonaws.com/hdfgroup/data/hdf5test/{filename} -P {data_dir}")
+
+            if system() == "Windows":
+                get_cmd = f"curl.exe -o {filename}\
+                            https://s3.amazonaws.com/hdfgroup/data/hdf5test/{filename}\
+                            --create-dirs --output-dir {data_dir}"
+            else:
+                get_cmd = f"wget -q\
+                            https://s3.amazonaws.com/hdfgroup/data/hdf5test/{filename}\
+                            -P {data_dir}"
+
+            rc = os.system(f"{get_cmd}")
             if rc != 0:
-                sys.exit("Failed to retreive test data file")
+                sys.exit(f"Failed to retreive test data file with error code {rc}")
     # run hsload for each file
     print(f"running hsload for {hdf5_path} to {test_folder}")
     rc = os.system(f"python ../../h5pyd/_apps/hsload.py {hdf5_path} {test_folder}")