diff --git a/src/classes/PRunBase.cpp b/src/classes/PRunBase.cpp
index f90c084c..dc57afab 100644
--- a/src/classes/PRunBase.cpp
+++ b/src/classes/PRunBase.cpp
@@ -73,7 +73,7 @@ PRunBase::PRunBase(PMsrHandler *msrInfo, PRunDataHandler *rawData, unsigned int
 {
   fValid = true;
 
-  fRunNo = runNo;
+  fRunNo = static_cast<int>(runNo);
   if ((runNo < 0) || (runNo > msrInfo->GetMsrRunList()->size())) {
     fRunInfo = 0;
     return;
diff --git a/src/classes/PTheory.cpp b/src/classes/PTheory.cpp
index a4e139e9..35b20167 100644
--- a/src/classes/PTheory.cpp
+++ b/src/classes/PTheory.cpp
@@ -526,9 +526,9 @@ double PTheory::Func(register double t, const vector<double>& paramValues, const
  *
  * \param name
  */
-unsigned int PTheory::SearchDataBase(TString name)
+int PTheory::SearchDataBase(TString name)
 {
-  unsigned int idx = THEORY_UNDEFINED;
+  int idx = THEORY_UNDEFINED;
 
   for (unsigned int i=0; i<THEORY_MAX; i++) {
     if (!name.CompareTo(fgTheoDataBase[i].fName, TString::kIgnoreCase) ||
@@ -557,7 +557,7 @@ void PTheory::MakeCleanAndTidyTheoryBlock(PMsrLines *fullTheoryBlock)
   char substr[256];
   TObjArray *tokens = 0;
   TObjString *ostr;
-  unsigned int idx = THEORY_UNDEFINED;
+  int idx = THEORY_UNDEFINED;
 
   for (unsigned int i=1; i<fullTheoryBlock->size(); i++) {
     // get the line to be prettyfied
@@ -580,7 +580,7 @@ void PTheory::MakeCleanAndTidyTheoryBlock(PMsrLines *fullTheoryBlock)
       }
     }
     // check if theory is indeed defined. This should not be necessay at this point but ...
-    if (idx == (unsigned int)THEORY_UNDEFINED)
+    if (idx == THEORY_UNDEFINED)
       continue;
     // check that there enough tokens. This should not be necessay at this point but ...
     if ((unsigned int)tokens->GetEntries() < fgTheoDataBase[idx].fNoOfParam + 1)
diff --git a/src/include/PRunBase.h b/src/include/PRunBase.h
index 53c03b15..07ae4b8c 100644
--- a/src/include/PRunBase.h
+++ b/src/include/PRunBase.h
@@ -77,7 +77,7 @@ class PRunBase
   protected:
     bool fValid;
 
-    unsigned int fRunNo;        ///< number of the run within the msr file
+    int fRunNo;                 ///< number of the run within the msr file
     PMsrHandler      *fMsrInfo; ///< msr-file handler
     PMsrRunStructure *fRunInfo; ///< run info used to filter out needed infos for the run
     PRunDataHandler  *fRawData; ///< holds the raw run data
diff --git a/src/include/PTheory.h b/src/include/PTheory.h
index e542de4f..ae42a6dc 100644
--- a/src/include/PTheory.h
+++ b/src/include/PTheory.h
@@ -166,7 +166,7 @@ class PTheory
     virtual double Func(register double t, const vector<double>& paramValues, const vector<double>& funcValues) const;
 
   private:
-    virtual unsigned int SearchDataBase(TString name);
+    virtual int SearchDataBase(TString name);
     virtual void MakeCleanAndTidyTheoryBlock(PMsrLines* fullTheoryBlock);
 
     virtual double Asymmetry(const vector<double>& paramValues, const vector<double>& funcValues) const;