diff --git a/lib/core/common.py b/lib/core/common.py
index 903663717..7b1285424 100644
--- a/lib/core/common.py
+++ b/lib/core/common.py
@@ -1670,6 +1670,10 @@ def runningAsAdmin():
     return isAdmin
 
 def logHTTPTraffic(requestLogMsg, responseLogMsg):
+    """
+    Logs HTTP traffic to the output file
+    """
+
     kb.locks.logLock.acquire()
 
     dataToTrafficFile("%s\n" % requestLogMsg)
@@ -1686,6 +1690,7 @@ def getPublicTypeMembers(type_, onlyValues=False):
     """
     Useful for getting members from types (e.g. in enums)
     """
+
     retVal = []
 
     for name, value in getmembers(type_):
@@ -1698,6 +1703,10 @@ def getPublicTypeMembers(type_, onlyValues=False):
     return retVal
 
 def enumValueToNameLookup(type_, value_):
+    """
+    Returns name of a enum member with a given value
+    """
+
     retVal = None
 
     for name, value in getPublicTypeMembers(type_):
@@ -1708,6 +1717,11 @@ def enumValueToNameLookup(type_, value_):
     return retVal
 
 def extractRegexResult(regex, content, flags=0):
+    """
+    Returns 'result' group value from a possible match with regex on a given 
+    content
+    """
+
     retVal = None
 
     if regex and content and '?P<result>' in regex:
@@ -1722,6 +1736,7 @@ def trimAlphaNum(value):
     """
     Trims alpha numeric characters from start and ending of a given value
     """
+
     while value and value[-1].isalnum():
         value = value[:-1]
 
@@ -1731,9 +1746,17 @@ def trimAlphaNum(value):
     return value
 
 def isNumPosStrValue(value):
+    """
+    Returns True if value is a string with a positive integer representation
+    """
+
     return value and isinstance(value, basestring) and value.isdigit() and value != "0"
 
 def aliasToDbmsEnum(value):
+    """
+    Returns major DBMS name from a given alias
+    """
+
     retVal = None
 
     for key, item in dbmsDict.items():
@@ -1746,7 +1769,7 @@ def aliasToDbmsEnum(value):
 def findDynamicContent(firstPage, secondPage):
     """
     This function checks if the provided pages have dynamic content. If they
-    are dynamic, proper markings will be made.
+    are dynamic, proper markings will be made
     """
 
     infoMsg = "searching for dynamic content"
@@ -2019,3 +2042,17 @@ def getComparePageRatio(firstPage, secondPage, filtered=False):
     conf.seqMatcher.set_seq2(secondPage)
 
     return conf.seqMatcher.quick_ratio()
+
+def openFile(filename, mode='r'):
+    """
+    Returns file handle of a given filename
+    """
+
+    try:
+        return codecs.open(filename, mode, conf.dataEncoding)
+    except IOError, e:
+        errMsg = "there has been a file opening error for filename '%s'. " % filename
+        errMsg += "Please check %s permissions on a file " % ("write" if mode and\
+          ('w' in mode or 'a' in mode or '+' in mode) else "read")
+        errMsg += "and that it's not locked by another process."
+        raise sqlmapFilePathException, errMsg
diff --git a/lib/core/dump.py b/lib/core/dump.py
index bcb520cb9..ce0ed9b6c 100644
--- a/lib/core/dump.py
+++ b/lib/core/dump.py
@@ -14,6 +14,7 @@ import os
 from lib.core.common import dataToDumpFile
 from lib.core.common import dataToStdout
 from lib.core.common import getUnicode
+from lib.core.common import openFile
 from lib.core.common import restoreDumpMarkedChars
 from lib.core.data import conf
 from lib.core.data import kb
@@ -259,7 +260,7 @@ class Dump:
                 os.makedirs(dumpDbPath, 0755)
 
             dumpFileName = "%s%s%s.csv" % (dumpDbPath, os.sep, table)
-            dumpFP = codecs.open(dumpFileName, "wb", conf.dataEncoding)
+            dumpFP = openFile(dumpFileName, "wb")
 
         count       = int(tableValues["__infos__"]["count"])
         separator   = str()
diff --git a/lib/core/option.py b/lib/core/option.py
index 5389f7c58..3812cc5e7 100644
--- a/lib/core/option.py
+++ b/lib/core/option.py
@@ -29,6 +29,7 @@ from lib.core.common import getFileItems
 from lib.core.common import getFileType
 from lib.core.common import normalizePath
 from lib.core.common import ntToPosixSlashes
+from lib.core.common import openFile
 from lib.core.common import parseTargetDirect
 from lib.core.common import parseTargetUrl
 from lib.core.common import paths
@@ -130,7 +131,7 @@ def __urllib2Opener():
     urllib2.install_opener(opener)
 
 def __feedTargetsDict(reqFile, addedTargetUrls):
-    fp = codecs.open(reqFile, "rb")
+    fp = openFile(reqFile, "rb")
 
     fread = fp.read()
     fread = fread.replace("\r", "")
@@ -1262,7 +1263,7 @@ def __saveCmdline():
 
             config.set(family, option, value)
 
-    confFP = codecs.open(paths.SQLMAP_CONFIG, "wb", conf.dataEncoding)
+    confFP = openFile(paths.SQLMAP_CONFIG, "wb")
     config.write(confFP)
 
     infoMsg = "saved command line options on '%s' configuration file" % paths.SQLMAP_CONFIG
@@ -1317,7 +1318,7 @@ def __mergeOptions(inputOptions):
 
 def __setTrafficOutputFP():
     if conf.trafficFile:
-        conf.trafficFP = codecs.open(conf.trafficFile, "w+", conf.dataEncoding)
+        conf.trafficFP = openFile(conf.trafficFile, "w+")
 
 def __basicOptionValidation():
     if conf.limitStart is not None and not (isinstance(conf.limitStart, int) and conf.limitStart > 0):