Rosell hailed Guardiola as the club's greatest ever coach, in a conciliatory move after Guardiola's comments last week pointed to a deep rift between them.
Guardiola, now coaching German and European champions Bayern Munich, accused Barcelona at a news conference last week of using its current coach Tito Vilanova's illness "to damage" him, without elaborating.
"We were very surprised by his comments. What he said about the board of directors and about Tito is completely false," Rosell said in an interview broadcast on Catalan television channel 8TV and posted online .
"In the press archives you will see how the club has treated him, the best coach in the history of the club."
Rosell urged supporters not to let the issue become a cause of division as he said disagreements with its legendary former player and coach Johan Cruyff had been.
"I ask the Barcelona fans to learn from the past, from what happened in the time of Johan, when the club was divided between 'Cruyffistas' and
non-Cruyffistas," he said.
"I ask that there not be Guardiolistas and non-Guardiolistas."
Guardiola, 42, whipped up a media storm last week with his rant.
Without saying who exactly had made the accusation, Guardiola denied that he had missed a chance to visit Vilanova while he was treated in New York for salivary gland cancer.
"Using Tito's illness to damage me is something I will never forget," he said.
Vilanova had been Guardiola's assistant at Barcelona for five years and he led the Catalan team to what Guardiola called their most successful league win in history last season.