Research into virtual worlds demonstrates that to successfully use virtual world platforms in different disciplines, certain limitations and potential difficulties of these platforms must be overcome. The current study extends previous research by investigating problems in integrating virtual worlds in education with a longitudinal observation of two cases and in perspectives of designers, practitioners and administrators. The purpose of this study was both to determine technical problems encountered by practitioners and designers who create environments in 3D virtual worlds for a certain purpose and to suggest practical strategies for these problems. In the study, designers experimented with two different 3D virtual world platforms for one year, to design and create learning environments. To collect the research data, interview records and design diaries in which the designers and practitioners noted problems that they encountered during two virtual world projects. The results indicate that the technical problems has not aroused only related the problems and those problems influenced several pedagogical issues like motivation of students and guidance in the environments. Our findings should be beneficial both to virtual world designers and to users who wish to use these environments in broad range of fields.