Migrating data from custom CMS to WordPress blog

I’m writting PHP script to convert custom CMS data to WordPress. All going perfect, except images attached to posts. Here is steps my script do to attach images to posts:

step 1 – insert new record in wp_posts table with this data:

• ID – auto increment
• post_author – 1 (admin)
• post_date, post_date_gmt, post_modified and post_modified_gmt – same string in format YYYY-MM-DD HH:MM:SS
• post_content – empty
• post_title – same as post_title from original post
• post_excerpt – empty
• post_status – inherit
• comment_status and ping_status – open
• post_password – empty
• post_name – image filename w/o extension
• to_ping and pinged – empty
• post_content_filtered – empty
• post_parent – ID of original post
• guid – full URL to image
• menu_order – 0
• post_type – attachment
• post_mime_type – image/jpeg
• comment_count – 0

step 2 – insert two new records to wp_postmeta table

• meta_id – auto increment
• post_id – ID of original post to which I attaching image
• meta_key – _wp_attached_file
• meta_value – YYYY/MM/image_filename_with_extension

and

• meta_id – auto increment
• post_id – ID of original post to which I attaching image
• meta_key – _wp_attachment_metadata
• meta_value – a:6:{s:5:"width";s:3:"250";s:6:"height";s:3:"165";s:14:"hwstring_small";s:23:"height='85' width='128'";s:4:"file";s:63:"/var/www/vhost/devel/wp-content/uploads/2005/02/picture3.jpg";s:5:"sizes";a:1:{s:9:"thumbnail";a:3:{s:4:"file";s:20:"picture3-150x150.jpg";s:5:"width";s:3:"150";s:6:"height";s:3:"150";}}s:10:"image_meta";a:10:{s:8:"aperture";s:1:"0";s:6:"credit";s:0:"";s:6:"camera";s:0:"";s:7:"caption";s:0:"";s:17:"created_timestamp";s:1:"0";s:9:"copyright";s:0:"";s:12:"focal_length";s:1:"0";s:3:"iso";s:1:"0";s:13:"shutter_speed";s:1:"0";s:5:"title";s:0:"";}}

step 3 – insert new record to wp_term_relationships table

• object_id – image ID from wp_posts table
• term_taxonomy_id – 9 (ID for taxonomy w/o description in wp_term_taxonomy table, same ID is assigned to new manualy attached images)
• term_order – 0

After this three steps, when I’m open Media -> Library in WP admin, for images automaticaly inserted with this script missing file type (JPG for other images) and thumbnail. If I try to Edit image, WP says Image data does not exist. Please re-upload the image. but if I cpopy&paste URL from File URL textbox to browser, I get image as I expect.

Image files are in expected path on disk, with proper permissions.

Where I’m wrong? What I’m missing to insert in WP base?

TIA